Urine test strips results chart meaning

Urine test strips results chart meaning DEFAULT

How to Read a Urine Dipstick

Medically reviewed by:

Luba Lee, FNP-BC, MS

Master's Degree, Nursing, University of Tennessee Knoxville

This article was medically reviewed by Luba Lee, FNP-BC, MS. Luba Lee, FNP-BC is a board certified Family Nurse Practitioner (FNP) and educator in Tennessee with over a decade of clinical experience. Luba has certifications in Pediatric Advanced Life Support (PALS), Emergency Medicine, Advanced Cardiac Life Support (ACLS), Team Building, and Critical Care Nursing. She received her Master of Science in Nursing (MSN) from the University of Tennessee in 2006. This article has been viewed 56,121 times.

Co-authors: 3

Updated: January 21, 2021

Views: 56,121

Categories: Urination

Medical Disclaimer

The content of this article is not intended to be a substitute for professional medical advice, examination, diagnosis, or treatment. You should always contact your doctor or other qualified healthcare professional before starting, changing, or stopping any kind of health treatment.

Sours: https://www.wikihow.com/Read-a-Urine-Dipstick

Urinalysis: how to interpret results

Urinalysis is an important screening and diagnostic tool, but health professionals must know how to perform the test and interpret results correctly for it to be beneficial. The article comes with a self-assessment enabling you to test your knowledge after reading it

Abstract

Analysing an individual’s urine can be a useful way of detecting or ruling out some diseases and infections. Urinalysis can be undertaken in many ways, one of which is using a reagent stick. To be effective, the test must be performed properly and the results interpreted correctly. This article gives an overview of the most important aspects of this investigation, highlighting signs to look for and what they may mean.

Citation: Yates A (2016) Urinalysis: how to interpret results. Nursing Times; Online issue 2, 1-3.

Author: Ann Yates is director of continence services, Cardiff and Vale University Health Board.

Introduction

Urine testing or urinalysis is a valuable tool to screen an patient and diagnose their health status. It provides valuable information about hydration, renal and urinary tracts, liver disease, diabetes mellitus and urinary-tract infections. Urine is formed in the kidneys and, through glomerular filtration, tubular reabsorption and tubular secretion, is how the body gets rid of its natural waste products (Marieb and Hoehn, 2010). Urinalysis is easy to undertake but results must be interpreted correctly.

Types of analysis

There are different ways of analysing urine and for different reasons, namely:

  • 24-hour collection: patient voids into toilet, then all urine is collected for the next 24 hours. As the body chemistry alters constantly, this is used to measure substances, such as steroids, white cells, electrolytes or determine urine osmolarity (Tortora and Derrickson, 2009);
  • First-morning specimen: first specimen of morning (or eight hours after recumbent position). Best sample for pregnancy testing;
  • Fasting specimen: the second voided specimen after a period of fasting;
  • Mid-stream urine (MSU): used to obtain urine for bacterial culture. First and last part of urine stream is voided into the toilet to avoid contaminating the specimen with organisms presenting on the skin;
  • Random specimen: for chemical or microscopic examination, a randomly collected specimen suitable for most screening purposes;
  • Catheter specimen of urine: collected for bacteriological examination if a patient’s symptoms suggest the presence of a UTI. The sampling technique used for collection is important (Baillie and Arrowsmith, 2005).

This article focuses on random specimen and MSU samples, and analysis using dipstick reagent strips.

Patient assessment/preparation

Urinalysis can potentially identify the presence of life-changing conditions, such as diabetes and renal disease. If abnormalities are detected, the individual may need further investigations, so they should be appropriately counselled to understand the implications before providing a sample. This has to be balanced against harm that could be caused by a missed diagnosis if urinalysis is not done.

Approximately 50ml of urine is required for urinalysis. Adults and children who are continent and can empty their bladder should either provide a random sample or be advised to provide an MSU sample. They should be mobile and dextrous enough to be able to do this, and be instructed in the technique to prevent contamination from hands or the genital area. Specific cleaning of the genital area seems not to affect contamination rates (Mousseau, 2001), but may be appropriate when personal hygiene is poor or faecal contamination is apparent.

Box 1 outlines the routine observations when undertaking urinalysis. The properties listed should be considered in line with clinical presentation, fluid intake and urine output. Before testing the urine using a reagent dipstick strip, the observations listed should be completed. The following factors can also affect results:

  • Use a fresh sample of urine (preferably less than 4 hours old or in line with the reagent strip manufacturer’s instructions to obtain accurate results. Bilirubin and urobilinogen are relatively unstable compounds when left in light or at room temperature;
  • Exposure of unpreserved urine to room temperature for a period of time can change pH and increase micro-organisms. If it cannot be tested immediately, the sample needs to be stored in line with the reagent strip manufacturer’s instructions or at 2-4°C and then brought to room temperature (15-20°C) before testing;
  • Bacterial growth of contaminated organisms may produce positive blood reactions;
  • Urine high in alkaline can show false positive results for protein;
  • Presence of glucose may reduce pH;
  • Presence of urea-splitting organisms may cause urine to become more alkaline (Dougherty and Lister, 2015).

Box 1. Routine observation of urine

Colour

This usually ranges from pale straw to deep amber, depending on concentration (Steggall, 2007).

  • Dark urine: may indicate dehydration
  • Brown/green or strong yellow: may indicate presence of bilirubin
  • Green: may indicate presence of pseudomonas infection or excretion of cytotoxic drugs, such as mitomycin
  • Bright red/red-brown: may indicate presence of blood (haematuria). Menstruation should be ruled out in females

Certain food or drugs may also influence colour; beetroot can produce a pinkish shade and rifampicin can turn urine orange/red.

Clarity

This is usually referred to as clear, slightly cloudy, cloudy or turbid.

Substances that can cause cloudiness but are not harmful include mucus, sperm, prostatic fluid and skin cells. Other substances that make urine cloudy are white/red blood cells, pus or bacteria that need attention. Frothy urine signifies protein in the urine.

Odour

Freshly voided urine may have a slight but inoffensive smell.

  • Fishy smell/ammonia: may indicate urinary infection
  • “Pear drop” or acetone smell: may indicate presence of ketones, as in diabetic ketoacidosis
  • Some strongly flavoured foods can also produce an odour, eg asparagus

Standard urine-test analysis

Many chemical reagent strips are available and differ between manufacturers. All detect a wide range of substances that can be identified in urine. The tests available include those for substances that are:

  • Produced by the body and naturally found in urine;
  • Produced by the body and not usually present in the urine;
  • Not normally found in the body.

The following test paddles are commonly featured on reagent strips: blood; bilirubin; urobilinogen; nitrite; leucocytes (white blood cells); protein; ketones; glucose; pH (a measure of how acidic or alkaline urine is); and specific gravity (relative density). It is important that the professional undertaking the test understands the manufacturer’s guidance before using the strip. Box 2 outlines the steps that should be followed when performing the urinalysis.

Box 2. Urinalysis using chemical reagent strips

  • Explain procedure to patient and gain consent
  • Comply with infection-prevention principles: wash hands, use protective equipment
  • Check expiry date on reagent-strip container and make sure it has been stored in line with the manufacturer’s recommendations
  • Advise patient how to collect a fresh sample, preferably a mid-stream sample if possible, as stored urine can give false results
  • Remove reagent dipstick from container, taking care to touch only the plastic handle; replace lid immediately
  • Observe urine for colour and clarity, then fully immerse reagent stick, so all reagent areas are covered. Hold for approximately two seconds. Remove strip from urine and tap on absorbent paper or against inside of urine container to remove excess urine
  • Wait for manufacturer’s recommended time to elapse, holding strip in horizontal position to prevent interaction between adjacent test pads
  • Compare reagent strip against colour reference guide on outside of container (Fig 1, attached)
  • If sample is not being sent to a laboratory for further investigations, dispose of urine, used strip, urine container and gloves, following local policy, and wash hands
  • Document results, and inform doctor and patient; take appropriate action as required

Significance of findings

Urine tests are frequently done in various settings, so it is vital that professionals understand how to interpret the common findings displayed on reagent strips and what they mean. This section will discuss each of the paddles identified on the strip.

Blood

Urine does not normally contain blood detected by reagent strips. Blood in the urine is known as haematuria and can be subclassified as follows:

  • Macroscopic: large volumes of blood in the urine, which takes on a rose or dark colour, especially if left to stand;
  • Microscopic: undetectable to the naked eye; reagent strips or a microscope are needed to identify it.

Blood can enter urine via damage to the filtration barrier in the kidneys that normally prevents blood from entering the urine or because of an abnormality to the structures that usually drain urine from the kidneys, store urine (bladder) or transport urine outside (urethra) (Bryant and Catto, 2008). Blood in the urine can be indicative of kidney disease; inflammatory lesions of the urinary tract (infection or cancer); renal damage; or kidney/renal stones.

It can also indicate a blood-clotting disorder or be a side-effect of anticoagulant drugs. Health professionals should also remember that urine can be contaminated with menstrual blood. Goddard et al (2010) highlighted that in most patients investigated for haematuria, no real presence of an underlying cause could be found and the haematuria was put down to a benign cause. However, as serious conditions cannot be identified unless investigated, it is important that haematuria is appropriately investigated unless a sensible reason, such as menstruation, can be identified.

Bilirubin and urobilinogen

Bilirubin is a chemical produced when red blood cells are broken down. It is transported in the blood to the liver, where it is processed and excreted into the gut as a constituent of bile. In the gut, bacteria acts on the bilirubin to transform it into urobiligen. It is usual for urine to contain urobiligen but not bilirubin. Bilirubin in the urine may be an indicator of a breakdown of red blood cells. It may not be effectively removed by the liver, which may suggest liver disease or a problem with drainage of bile into the gut, such as gall stones.

Nitrites

Nitrites are not usually found in urine and are associated with the presence of bacteria that can convert nitrate into nitrite. The presence of nitrites can be suggestive of a UTI but clinical presentation of symptoms should also be taken into account. The absence of nitrites, however, does not always rule out the presence of a UTI; Devillé et al (2004) identified that in approximately 50% of urine samples containing bacteria, the nitrites test was negative.

Leucocytes (white blood cells)

In urine, leucocytes are usually associated with a urinary infection but sometimes may indicate a more severe renal problem (Steggall, 2007). When white blood cells are present in the urine, patients are said to have pyuria (pus in the urine). To establish the cause, a clean-catch urine sample should be examined under a microscope, cultured to see what bacteria grows and tested for sensitivity to establish antibiotic treatment. Where no bacterial cells are detected, the patient is said to have sterile pyuria; this can occur in tuberculosis and inflammatory disease of the kidneys (Higgins, 2007).

Protein

In a healthy person, urine does not contain a level of protein that is detectable on a urine reagent strip. This is due to the protein molecules being too large to pass through the glomerular filtration barrier. When protein can pass through this barrier, it is known as proteinuria. Proteinuria can be caused by many things, such as damage or disease to the glomerular filtration barrier; hypertension; kidney damage; diabetes mellitus; and pre-eclampsia (Mulryan, 2011). Specific investigations will be required to detect the cause of proteinuria.

Ketones

These are chemicals that are formed during the abnormal breakdown of fat and are not normal constituents of urine. Breakdown of fat may result from prolonged vomiting, fasting or starvation; individuals on a diet or who present with diarrhoea and vomiting may have a positive result. Ketones can also be present in the urine of people with poorly controlled diabetes. This can make the blood more acidic and is known as diabetic ketoacidosis; it should be reviewed urgently by a doctor. Some medications, such as captopril, may also produce a false positive result (Steggall, 2007).

Glucose

Glucose in the urine (glycosuria) can occur in pregnancy or patients taking corticosteroids. It may also be indicative of diabetes mellitus but is not a normal constituent of urine. Although glycosuria is an indication of endocrine abnormality, it is not diagnostic and further investigation, such as fasting blood tests, may be required.

pH

This is a measure of acidity or alkalinity in urine. All urine will give a pH reading on analysis and it is usually slightly acidic. A range of 5.0-8.0 is considered normal (Higgins, 2007). Acidic urine may indicate formation of urinary stones, while alkaline urine may indicate a UTI with certain types of bacteria, such as Proteus mirabilis, Klebsiella or Pseudomonas (Higgins, 2007). However, pH is also affected by diet; a high protein intake can give rise to acidic urine, whereas a high intake of dairy products or vegetables can give rise to alkaline urine. UTIs and medication can also result in alkaline urine. Results should be interpreted in conjunction with an individual’s specific presentation.

Specific gravity (SG) (relative density)

Urine can range from very diluted to very concentrated; its density is measured against pure water at room temperature and pressure. Specific gravity identifies the hydration of an individual – a well-hydrated person will have diluted urine whereas someone who is dehydrated will present with concentrated urine. The normal range of specific gravity is 1.001-1.035.

Diluted urine could occur in an individual who has high fluid intake; diabetes insipidus; hypercalcaemia; endocrine disorders, such as kidney disease; or failed to produce anti-diuretic hormone.

Concentrated urine can be the result of dehydration. When assessing specific gravity, environmental factors such as temperatures should be taken into account.

Conclusion

Urinalysis using a dipstick reagent strip is an effective screening tool to assess the health status of an individual and detect some diseases and infections. It is important that professionals understand methods for collecting urine, limit the risk of contamination by using reagent strips correctly and accurately interpret results.

Key points

  • Urinary dipstick reagent strips are a quick, effective screening aid to urinalysis
  • Nursing staff should understand the importance of examining urine for colour, clarity and odour before undertaking dipstick analysis
  • Urine can be collected in different ways to limit contamination
  • Nursing staff should be able to carry out the procedure correctly and accurately interpret the results
  • Different components of the reagent strip have different clinical implications

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Baillie L, Arrowsmith V (2005) Meeting elimination needs. In: Baillie L (ed) Developing Practical Nursing Skills. London: Hodder Arnold.

Bryant RJ, Catto JWF (2008) Haematuria. Surgery; 26: 4, 150-153.

Devillé W et al (2004) The urine dipstick test useful to rule out infections. A meta-analysis of the accuracy. BMC Urology; 4: 4.

Dougherty L, Lister S (2015) The Royal Marsden Hospital Manual of Clinical Nursing Procedure. Chichester: Wiley-Blackwell

Goddard J et al (2010) Kidney and urinary tract disease. In: Colledge NR et al (eds) Davidson’s Principles and Practice of Medicine. London: Churchill Livingstone.

Higgins C (2007) Understanding Laboratory Investigations: for Nurses and health professionals. Oxford: Blackwell Publishing.

Marieb EN, Hoehn K (2010) Human Anatomy and Physiology. San Francisco, CA: Pearson Benjamin Cummings.

Mousseau J (2001) Contamination of urine specimens from women with acute dysuria did not differ with collection technique. Evidence Based Nursing; 4: 46.

Mulryan C (2011) Urine testing through the use of dipstick analysis. British Journal of Healthcare Assistants; 5: 5, 234-239.

Steggall MJ (2007) Urine samples and urinalysis. Nursing Standard; 22: 14, 42-45.

Tortora GJ, Derrickson B (2009) Principles of Anatomy and Physiology. Hoboken, NJ: John Wiley and Sons.

Assessment skills: continenceNewly qualified nurses: practical procedures2016-06-07

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10 Parameter Urinalysis Test at Home

A urinalysis is a test of your urine. Urine is produced by the kidneys. The kidneys filter wastes out of the blood, help regulate the amount of water in the body, and conserve proteins, electrolytes, and other compounds that the body can reuse. Therefore, by examining the composition of urine, many disorders can be detected. A typical 10 parameter urinalysis test strip (dipstick) is lined with 10 different reagent test pads that change color in response to the chemical characteristics of the urine and can help in general monitoring of health as well as detection of a broad spectrum of abnormalities. This is the same kind of test medical professionals use to assist in diagnosis.

A home-use urinalysis strip can enable you to monitor your health from the convenience of your home without going to a medical professional for a Urinalysis test every time you think you have some issue, which can be very expensive and time consuming.

10 Tests in One

  • Glucose
  • Protein
  • pH
  • Leukocytes
  • Nitrites
  • Ketones
  • Bilirubin
  • Blood
  • Urobilinogen
  • Specific Gravity

Urinalysis can assist in diagnosis and monitoring of many metabolic or systemic diseases that can go unnoticed because they haven’t produced striking signs or symptoms yet.

Directions to Use

1. Immerse

Immerse the strip into the urine sample and remove immediately by dragging the edge of the strip against the container rim to remove excess urine. If reading the strip visually, start timing. Always use fresh urine specimen in a clean, dry container.

2. Wait

Place the strip horizontally on a paper towel or tissue to remove excess and wait until results are ready to be read. The reading time for different tests is provided on the product packaging or package insert.

3. Compare

Compare each test pad to the corresponding row of color chart (see the example color chart below) on the package insert (or packaging) to find the closest match. Read the results carefully within 60 seconds in a good light. Usually changes in color that appears after 2 minutes are of no diagnostic significance.

Color Chart

Color Chart for 10 Parameter Urinalysis Test

Interpretation of Results

Glucose

Glucose is normally not present in urine. When glucose is present, the condition is called glucosuria. This often happens if there is abnormally high level of glucose present in the blood. Normal glucose range in urine is 0 to 0.8 mmol/l (0 to 15 mg/dL). Higher values may occur with diabetes, pregnancy, or renal glycosuria.

Bilirubin

Bilirubin is a yellowish pigment found in bile, a fluid produced by the liver. Bilirubin is not present in the urine of normal, healthy individuals. Increased bilirubin levels indicate different forms of liver disease, e.g., cirrhosis, hepatitis, gallstone, biliary tract disease and is an early indicator of jaundice development. Even trace amounts of bilirubin are sufficiently abnormal to require further investigation.

Ketones

Ketones are produced when the body burns fat for energy or fuel. They are also produced when you lose weight or if there is not enough insulin to help your body use sugar for energy. Ketones are not normally found in the urine. They can form when a person does not eat enough carbohydrates (for example, in cases of fasting, starvation, or high-protein diets) or when a person’s body cannot use carbohydrates properly. When carbohydrates are not available, the body metabolizes fat instead to get the energy it needs to keep functioning. Increased ketone levels is a sign of insufficient insulin and can be detected in diabetes, starvation, vomiting, digestive disorders, pregnancy and febrile states. If you are on a Ketone diet, detecting ketones in urine is indicative of metabolic state called ketosis which leads to weight loss and fat burning.

Specific Gravity

Urine specific gravity is a measure of concentration of all chemical particles in the urine.

Healthy adults have urine specific gravity ranging from 1.003 to 1.030. Reduced specific gravity indicates diabetes and other renal disorders while elevated levels indicate liver disease, excessive loss of free water, or congestive heart failure. A higher than normal concentration often is a result of not drinking enough fluids.

Blood

Blood in the urine is not a normal finding, but it is not uncommon and not necessarily a cause for alarm. Your healthcare practitioner will investigate further to try to determine the source and underlying cause. It may be a sign of kidney damage, infection, kidney or bladder stones, kidney or bladder cancer, or blood disorders. Blood is often, but not always, found in the urine of menstruating females.

PH

A urine pH test measures the level of acid in urine. Normal urine is slightly acidic, with pH value ranging from 5 to 8. A high urine pH (>8) may be due to kidneys that do not properly remove acids, or due to kidney failure, stomach pumping (gastric suction), urinary tract infection, or vomiting. A low urine pH may be due to diabetic ketoacidosis, diarrhea, too much acid in the body fluids (metabolic acidosis), such as diabetic ketoacidosis, and starvation. It is an important indicator of kidney, gastrointestinal, respiratory and metabolic health.

Protein

A protein in urine test measures how much protein is in your urine. Proteins are substances that are essential for the body to function properly. Protein is normally found in the blood. If there is a problem with kidneys, protein can leak into the urine. While a small amount is normal, a large amount of protein in urine may indicate kidney disease. When urine protein is elevated, a person has a condition called proteinuria. Persistently elevated levels of protein in urine can be the result of urological and nephrological disorders and require medical intervention.

Urobilinogen

Urobilinogen is formed from the reduction of bilirubin. Bilirubin is a yellowish substance found in the liver that helps break down red blood cells. Normal urine contains some urobilinogen (up to 1.0 mg/dL). If there is little or no urobilinogen in urine, it can mean liver isn’t working correctly. Too much urobilinogen (> 2 mg/dL) in urine may indicate a liver disease such as hepatitis or cirrhosis.

Nitrite

Normal urine contains chemicals called nitrates. If bacteria enter the urinary tract, nitrates can turn into different, similarly named chemicals called nitrites. Nitrites in urine may be a sign of a urinary tract infection (UTI). To detect UTI, presence of Leukocyte in urine is also considered. UTI can be present despite a negative Nitrite test.

Leukocyte

Leukocytes (white blood cells) are the cells of the immune system that are involved in protecting the body against both infectious diseases and foreign invaders. A few white blood cells are normally present in urine and generally yield negative results. When the number of WBCs in urine increases significantly, this screening test will become positive. The presence of leukocytes (>10 cacells/uL) in urine may indicate infections in the urinary tract or kidneys.

Track Your Urinalysis Data with Urinox Mobile App

Use Urinox app on Google Play Store to easily enter, store and track your urinalysis data. You can view the data in graphical form and share it with your medical professional if required.

Sources:

  • mayoclinic.org
  • webmd.com
  • medlineplus.gov
Sours: https://www.diagnoxhealth.com/10-parameter-urinalysis-test-at-home/
How to read Urine Testing strips results What can you test for with a urine dip test strip ?

Urine test strip

Urine test strip
Chemstrip1.jpg

The Multistix urine test strip showing the manufacturer’s coloured scale.

Purposedetermine pathological changes

A urine test strip or dipstick is a basic diagnostic tool used to determine pathological changes in a patient's urine in standard urinalysis.[1]

A standard urine test strip may comprise up to 10 different chemical pads or reagents which react (change color) when immersed in, and then removed from, a urine sample. The test can often be read in as little as 60 to 120 seconds after dipping, although certain tests require longer. Routine testing of the urine with multiparameter strips is the first step in the diagnosis of a wide range of diseases. The analysis includes testing for the presence of proteins, glucose, ketones, haemoglobin, bilirubin, urobilinogen, acetone, nitrite and leucocytes as well as testing of pH and specific gravity or to test for infection by different pathogens.[2]

The test strips consist of a ribbon made of plastic or paper of about 5 millimetre wide, plastic strips have pads impregnated with chemicals that react with the compounds present in urine producing a characteristic colour. For the paper strips the reactants are absorbed directly onto the paper. Paper strips are often specific to a single reaction (e.g. pH measurement), while the strips with pads allow several determinations simultaneously.[2]

There are strips which serve different purposes, such as qualitative strips that only determine if the sample is positive or negative, or there are semi-quantitative ones that in addition to providing a positive or negative reaction also provide an estimation of a quantitative result, in the latter the colour reactions are approximately proportional to the concentration of the substance being tested for in the sample.[2] The reading of the results is carried out by comparing the pad colours with a colour scale provided by the manufacturer, no additional equipment is needed.[3]

This type of analysis is very common in the control and monitoring of diabetic patients.[2] The time taken for the appearance of the test results on the strip can vary from a few minutes after the test to 30 minutes after immersion of the strip in the urine (depending on the brand of product being used).

Semi-quantitative values are usually reported as: trace, 1+, 2+, 3+ and 4+; although tests can also be estimated as milligrams per decilitre. Automated readers of test strips also provide results using units from the International System of Units.[2]

Test method[edit]

The test method consists of immersing the test strip completely in a well mixed sample of urine for a short period of time, then extracting it from the container and supporting the edge of the strip over the mouth of the container to remove excess urine. The strip is then left to stand for the time necessary for the reactions to occur (usually 1 to 2 minutes), and finally the colours that appear are compared against the chromatic scale provided by the manufacturer.

An improper technique can produce false results, for example, leukocytes and erythrocytes precipitate at the bottom of the container and may not be detected if the sample is not properly mixed, and in the same way, if an excess of urine remains on the strip after it has been removed from the test sample, may cause the reagents to leak from the pads onto adjacent pads resulting in mixing and distortion of the colours. To ensure that this does not occur it is recommended the edges of the strip are dried on absorbent paper.[2]

Reactions for generalised tests[edit]

Comparison between two reactive strips, one pathological (to the left, from a patient with uncontrolled diabetes mellitus), and an unreacted strip. From top to bottom the pathological strip shows: Leukocytes (-), nitrites (-), urobilinogen (-), proteins (+), pH (5), hemoglobin (+), specific gravity (1.025), ketones (++++), bilirubin (+), glucose (+++).

pH[edit]

The lungs and kidneys are the main regulators of an organism's acid / alkali balance. The balance is maintained through the controlled excretion of acidic hydrogens in the form of ammonia ions, monohydrogenated phosphate, weak organic acids and through the reabsorption of bicarbonate through glomerular filtration in the convoluted tubules of the nephron. The pH of urine normally vary between 4.5 and 8 with the first urine produced in the morning generally being more acidic and the urine produced after meals generally more alkaline.[4] Normal reference values are not provided for urine pH as the variation is too wide and results have to be considered in the context of the other quantifiable parameters.[4]

The determination of urinary pH has two main objectives, one is diagnostic and the other is therapeutic. On the one hand it provides information regarding the balance between acid and alkali in a patient and allows identification of the substances that are present in the urine in crystalline form. On the other hand, certain illnesses require a patient to keep the pH of their urine within given narrow margins, whether to promote the elimination of chemotherapeutic agents, avoid the precipitation of salts that promote the formation of kidney stones, or in order to facilitate the control of a urinary infection. Regulating diet mainly controls urinary pH, although using medication can also control it. Diets rich in animal proteins tend to produce acidic urine, while diets mainly composed of vegetables tend to produce alkali urine.[4]

Commercial brands measure pH in increments of 0.5 or 1 pH units between pH 5 and 9. In order to differentiate pH in this wide range it is common to use a double indicator system comprising methyl red and bromothymol blue.[5] Methyl red produces a colour change from red to yellow in the range of pH 4 to 6 and the bromothymol blue changes from yellow to blue between pH 6 and 9. In the range 5 to 9 the strips show colours that change from orange at pH 5, passing through yellow and green to dark blue at pH 9.[6]

Specific gravity[edit]

Main article: Urine Specific Gravity

One of the kidneys’ important functions is to reabsorb water after glomerular filtration. The complex process of reabsorption is usually one of the first renal functions to be affected by disease. The specific gravity of urine is a measure of its density compared to H2O and depends on the quantity and density of solutes (molecules with more mass per volume increase measure of specific gravity). The measurement of specific gravity should not be confused with the measurement of osmotic concentration, which is more related to the number of particles than with their mass.[7]

The urine test strip test for specific gravity is based on the change in dissociation constant (pKa) of an anionic polyelectrolyte (poly-(methyl vinyl ether/maleic anhydride)) in an alkali medium that is ionised and releases hydrogen ions in proportion to the number of cations present in the solution.[6] The greater the cation concentration of the urine the more hydrogen ions are released, thereby reducing the pH. The pad also includes bromothymol blue, which measures this change in pH.[6][8] It should be remembered that the test strip only measures cation concentration, it is therefore possible that urine with a high concentration of non-ionic solutes (such as glucose or urea) or with high molecular weight compounds (such as the media used to provide radiographic contrast) will yield a result that will be erroneously lower than that measured by densitometry. The colours vary from dark blue with a reading of 1.000 to yellow for a reading of 1.030.[8][9]

  1. In an alkaline medium

    Polyelectrolyte-Hn + Cationsn+ → Polyelectrolyte-Cations + nH+

  2. In an alkaline medium

    H+ + Bromothymol blue(Blue) → Bromothymol blue-H+(Yellow)

Elevated protein concentrations produce slightly elevated specific density results as a consequence of the indicator's protein error; in addition, samples with a pH above 6.5 give lower readings as a result of the indicator's bias. For this reason the manufacturers recommend that 5 units are added to the specific gravity reading when the pH is greater than 6.5.[8]

Blood[edit]

Blood may be present in the urine either in the form of intact red blood cells (hematuria) or as the product of red blood cell destruction, hemoglobin (hemoglobinuria). Blood present in large quantities can be detected visually. Hematuria produces cloudy red urine, and hemoglobinuria appears as a clear red specimen. Any amount of blood greater than five cells per microliter of urine is considered clinically significant; visual examination cannot be relied upon to detect the presence of blood. Microscopic examination of the urinary sediment shows intact red blood cells, but free hemoglobin produced either by hemolytic disorders or lysis of red blood cells is not detected. Therefore, chemical tests for hemoglobin provide the most accurate mean for determining the presence of blood. Once blood has been detected, the microscopic examination can be used to differentiate between hematuria and hemoglobinuria.

Chemical tests for blood use the pseudoperoxidase activity of hemoglobin to catalyze a reaction between the heme component of both hemoglobin and myoglobin and the chromogen (a substance that acquires colour after a chemical reaction) tetramethylbenzidine to produce an oxidized chromogen, which has a green-blue colour. Reagent strip manufacturers incorporate peroxide, and tetramethylbenzidine, into the blood testing area. Two colour charts are provided that correspond to the reactions that occur with hemoglobinuria, myoglobinuria and hematuria (RBCs). In the presence of free hemoglobin/myoglobin, uniform colour ranging from a negative yellow through green to a strongly positive green-blue appears on the pad. In contrast, intact red blood cells are lysed when they come in contact with the pad, and the liberated hemoglobin produces an isolated reaction that results in a speckled pattern on the pad. Reagent strip tests can detect concentrations as low as five red blood cells per microliter; however, care must be taken when comparing these figures with the actual microscopic values, because the absorbent nature of the pad attracts some of urine. The terms trace, small, moderate, and large (or trace, 1+, 2+, and 3+) are used for reporting.

False-positive reactions due to menstrual contamination may be seen. They also occur if strong oxidizing detergents are present in the specimen container. Vegetable peroxidase and bacterial enzymes, including an Escherichia coli peroxidase, may also cause false-positive reactions. Therefore, sediments containing bacteria should be checked closely for the presence of red blood cells. Traditionally, ascorbic acid (vitamin C) has been associated with false-negative reagent strip reactions for blood. Both Multistix and Chemstrip have modified their reagent strips to reduce this interference to very high levels of ascorbic acid, and Chemstrip overlays the reagent pad with an iodate-impregnated mesh that oxidizes the ascorbic acid prior to its reaching the reaction pad. False-negative reactions can result when urine with a high specific gravity contains crenated red blood cells that do not lyse when they come in contact with the reagent pad. Decreased reactivity may also be seen when formalin is used as a preservative or when the hypertension medication captopril or high concentration of nitrite are present. Red blood cells settle to the bottom of the specimen container, and failure to mix the specimen prior to testing causes a falsely decreased reading.[10]

Diseases identified[edit]

With the aid of routine examinations early symptoms of the following four groups can be identified:

  • Diseases of the kidneys and the urinary tract
  • Carbohydrate metabolism disorders (diabetes mellitus)
  • Liver diseases and haemolytic disorders
  • Urinary infections

Urinary tract[edit]

Screening parameters: Many renal and urinary tract diseases may be asymptomatic for a long period of time. Routine urinalysis is recommended as a basic yet fundamental step in identifying renal damage and/or urinary tract disease at an early stage, especially in high-risk populations such as diabetics, the hypertensive, African Americans, Polynesians, and those with a family history.[11]

Specific kidney and urinary tract diseases that can be identified include: chronic kidney disease, glomerulonephritis, proteinuria and haematuria.

Protein testing[edit]

Of the routine chemical tests performed on urine, the most indicative of renal disease is the protein determination. Proteinuria is often associated with early renal disease, making the urinary protein test an important part of any physical examination. Normal urine contains very little protein, usually less than 100–300 mg/L or 100 mg per 24 hours is excreted. This protein consists primarily of low-molecular-weight serum proteins that have been filtered by the glomerulus and proteins produced in the genitourinary tract. Due to its low molecular weight, albumin is the major serum protein found in the plasma, the normal urinary albumin content is low because the majority of albumin presented in the glomerulus is not filtered, and much of the filtered albumin is reabsorbed by the tubules. Other proteins include small amounts of serum and tubular microglobulins. Uromodulin produced by the renal tubular epithelial cells and proteins from prostatic, seminal, and vaginal secretions. Uromodulin is routinely produced in the distal convoluted tube, and forms the matrix of casts.

Traditional reagent strip testing for protein uses the principle of the protein error of indicators to produce a visible colorimetric reaction. Contrary to the general belief that indicators produce specific colours in response to particular pH levels, certain indicators change colour in the presence of protein even though the pH of the medium remains constant. This is so because protein accepts hydrogen ions from the indicator. The test is more sensitive to albumin because albumin contains more amino groups to accept the hydrogen ions than other proteins. Depending on the manufacturer, the protein area of the strip contains different chemicals. Multistix contains tetrabromophenol blue and Chemstrip contains 3’,3”,5’,5”-tetrachlorophenol, 3,4,5,6-tetrabromosulfonphthalein. Both contain an acid buffer to maintain the pH at a constant level. At a pH level of 3, both indicators appear yellow in the absence of protein. However, as the protein concentration increases, the colour progresses through various shades of green and finally to blue. Readings are reported in terms of negative, trace, 1+, 2+, 3+ and 4+ or the semi-quantitative values of 30, 100, 300 or 2000 mg/dL corresponding to each colour change. Trace values are considered to be less than 30 mg/dL. Interpretation of trace readings can be difficult.[12]

Indicator-H+(Yellow) + Protein → Indicator(Blue-green) + Protein-H+

The major source of error with reagent strips occurs with highly buffered alkaline urine that overrides the acid buffer system, producing a rise in pH and a colour change unrelated to protein concentration. Likewise, a technical error of allowing the reagent pad to remain in contact with the urine for a prolonged period may remove the buffer. False-positive readings are obtained when the reaction does not take place under acidic conditions. Highly pigmented urine and contamination of the container with quaternary ammonium compounds, detergents and antiseptics also cause false-positive readings. A false-positive trace reading may occur in specimens with a high specific gravity.

Hemoglobin and myoglobin testing[edit]

Microphotograph of a macroscopic hematuria, the biconcave form of the red blood cellsis clearly visible, it is rare to find examples in such a well conserved condition.

The presence of blood in the urine is, of all the parameters normally tested, the one that is most closely related with traumatic damage to the kidneys or the genitourinary tract. The most common causes of hematuria are: nephrolithiasis, glomerular disease, tumours, pyelonephritis, exposure to nephrotoxins, and treatment with anticoagulants. Non-pathological hematuria can be observed after strenuous exercise and during menstruation. The normal number of red blood cells in urine should not usually exceed 3 per high power field.[13]

A urine test strip showing positive for blood can also indicate hemoglobinuria, which is not detectable using a microscope due to the lysis of red blood cells in the urinary tract (particularly in alkaline or dilute urine), or intravascular hemolysis. Under normal conditions the formation of haptoglobin-hemoglobin complexes prevents glomerular filtration, but if the hemolysis is extensive haptoglobin's uptake capacity is exceeded and hemoglobin can appear in urine. Hemoglobinuria can be caused by hemolytic anaemia, blood transfusions, extensive burns, the bite of the recluse spider (Loxosceles), infections and strenuous exercise.

The urine test strip test for blood is based on hemoglobin's pseudo peroxidase activity in catalysing a reaction between hydrogen peroxide and the chromogen tetramethylbenzidine in order to produce a dark blue oxidation product.[6][13] the resultant colour can vary between green and dark blue depending on the amount of hemoglobin.[13]

  • Catalysed by hemoglobin acting as a peroxidase

    H2O2 + Chromogen → Oxidised chromogen (coloured) + H2O

    The reaction is not only catalysed by blood hemoglobin, other globins with a hem group such as myoglobin can also catalyse the same reaction.[13]

The presence of myoglobin in urine gives a positive reaction in the test strip's blood test but the urine appears clear with a red to brown colouration. The presence of myoglobin in place of hemoglobin can be caused by pathologies associated with muscular damage (rhabdomyolysis), such as trauma, crush syndrome, prolonged coma, convulsions, progressive muscular atrophy, alcoholism, heroin abuse and strenuous physical activity.

The haem fraction of these proteins is toxic for the kidney tubules and elevated concentrations can cause acute kidney injury.

It is possible to use an ammonia sulphate precipitation test in order to distinguish between hemoglobinuria and myoglobinuria. This consists of adding 2.8gr of ammonia sulphate to 5 ml of centrifuged urine, mixing well and after 5 minutes filtering the sample and centrifuging again. The hemoglobin precipitates out with the ammonia sulphate but not the myoglobin. Analysis of the supernatant for blood with a test strip will give a positive if myoglobin is present and a negative if hemoglobin is present.

The test can give false positives if strong oxidant or peroxide residues are present on the laboratory material used for the analysis.[13]

Carbohydrate disorders[edit]

Around 30–40% of type I diabetics and around 20% of type II diabetics suffer in time from a nephropathy, and early recognition of diabetes is therefore of major significance for the further state of health of these patients.

Specific carbohydrate metabolism disorders able to be identified include Diabetes Mellitus, Glucosuria and Ketonuria.

Glucose test[edit]

Under normal conditions nearly all the glucose removed in the glomerulus is reabsorbed in the proximal convoluted tubule. If the blood glucose level increases, as happens in diabetes mellitus, the capacity of the convoluted tubule to reabsorb glucose is exceeded (an effect known as renal reabsorption threshold). For glucose this threshold is between 160–180 mg/dl. Glucose concentrations vary in an individual, and a healthy person can present with transitory glucosuria after a meal high in sugars; therefore the most representative results come from samples obtained at least two hours after food is eaten.

The detection of glucose by test strips is based on the enzymatic reaction of glucose oxidase. This enzyme catalyses the oxidation of glucose by atmospheric oxygen to form D-glucono-δ-lactone and hydrogen peroxide. A second linked reaction, mediated by a peroxidase, catalyses the reaction between the peroxide and a chromogen (a substance that acquires colour after a chemical reaction) to form a coloured compound that indicates the glucose concentration.[6]

  • 1) Catalysed by glucose oxidase

    Glucose + O2 → D-glucono-δ-lactone + H2O2

  • 2) Catalysed by peroxidase

    H2O2 + Chromogen → Oxidised chromogen (coloured) + H2O

The reaction is specific for glucose, as occurs in all enzymatic reactions, but it can provide some false positive results due to the presence of traces of strong oxidising agents or peroxide from disinfectants used on laboratory instruments.[6]

Ketone test[edit]

The term ketones or ketone bodies in reality refers to three intermediate products in the metabolism of fatty acids; acetone, acetoacetic acid and beta-hydroxybutyric acid. Elevated concentrations of ketones are not generally found in urine, as all these substances are completely metabolized, producing energy, carbon dioxide and water. However, the disruption of carbohydrate metabolism can lead to metabolic imbalances and the appearance of ketones as a by-product of the metabolism of an organism's fat reserves.

An increase in fat metabolism can be the result of starvation or malabsorption, the inability to metabolize carbohydrates (as occurs, for example, in diabetes) or due to losses from frequent vomiting.

The control of urinary ketone is particularly useful in managing and monitoring diabetes mellitus type 1. Ketonuria indicates an insulin deficiency that indicates the need to regulate its dosage. An increase in the blood concentration of ketone produces a water-electrolyte imbalance, dehydration and if not corrected, acidosis and in the end diabetic coma.

The three ketone compounds appear in different proportions in the urine, although these proportions are relatively constant in different samples as both the acetone and the beta-hydroxybutyric acid are produced from the acetoacetic acid. The proportions are 78% beta-hydroxybutyric acid, 20% acetoacetic acid and 2% acetone.

The test used in the urine test strips is based on the reaction of sodium nitroprusside (nitroferricyanide). In this reaction the acetoacetic acid in an alkali medium reacts with the sodium nitroprusside producing a magenta coloured complex:[6][14]

  • Na2[Fe(CN)5NO] + CH3COCH2COOH + 2Na(OH) → Na4[Fe(CN)5-N=CHCOCH2COOH](magenta) + H2O

  • Sodium nitroprusside + Acetoacetic acid + Alkali medium → Pink-magenta complex + Water

The test does not measure beta-hydroxybutyric acid and it is only weakly sensitive to acetone when glycine is added to the reaction. However, as these compounds are derived from the acetoacetic acid their existence can be assumed and a separate test is not therefore necessary. Those medicines that contain sulfhydryl groups, such as mercaptoethane sulphonate Na (Mesna) and captopril and L-DOPA can give atypical colouring. A false negative can occur in samples that have not been adequately stored due to volatilization and bacterial degradation.

Liver and blood disorders[edit]

In many liver diseases the patients often show signs of pathology only at a late stage. Early diagnosis allows appropriate therapeutic measures to be instituted in good time, avoiding consequential damage and further infections.

Specific liver diseases and haemolytic disorders able to be identified include liver disease, (accompanied by jaundice), cirrhosis, urobilinogenuria and bilirubinuria.

Bilirubin test[edit]

Bilirubin is a highly pigmented compound that is a by-product of haemoglobin degradation. The haemoglobin that is released after the mononuclear phagocyte system (located in the liver and spleen) withdraws old red blood cells from circulation is degraded into its components; iron, protoporphyrin and protein. The system's cells convert the protoporphyrin into unconjugated bilirubin that passes through the circulatory system bound to protein, particularly albumin. The kidney is unable to filter out this bilirubin as it is bound to protein, however, it is conjugated with glucuronic acid in the liver to form water-soluble conjugated bilirubin. This conjugated bilirubin does not normally appear in the urine as it is excreted directly from the intestine in bile. Intestinal bacteria reduce the bilirubin to urobilinogen, which is later oxidised and either excreted with the faeces as stercobilin or in the urine as urobilin.

Conjugated bilirubin appears in urine when the normal degradation cycle is altered due to the obstruction of the biliary ducts or when the kidney's functional integrity is damaged. This allows the escape of conjugated bilirubin into the circulation as occurs in hepatitis and hepatic cirrhosis).

The detection of urinary bilirubin is an early indication of liver disease and its presence or absence can be used to determine the causes of clinical jaundice.

The jaundice produced by the accelerated destruction of red blood cells does not produce bilirubinuria, as the high serum bilirubin is found in the unconjugated form and the kidneys are unable to excrete it.

The test strips use a diazotization reaction in order to detect bilirubin. The bilirubin combines with a diazonium salt (2,4-dichloroaniline or 2,6-dichlorobenzene-diazonium-tetrafluoroborate) in an acid medium to produce an azo dye with colouration that varies from pink to violet:[6]

  • In acid medium

    Bilirubin glucuronide + Diazonium salt→ Azo dye (violet)

False positive reactions can be due to unusual pigments in the urine (for example, yellowy orange phenazopyridine metabolites, indican and the metabolites of the medicine Lodine (Etodolac)). False negatives can also be given by poorly stored samples as the bilirubin is photosensitive and undergoes photo oxidation to biliverdin when it is exposed to light, or hydrolysis of the glucuronide can occur producing free bilirubin which is less reactive.[6]

Urobilinogen test[edit]

Intestinal bacteria convert the conjugated bilirubin that is excreted by the bile duct into the intestine into urobilinogen and stercobilinogen. Part of the urobilinogen is reabsorbed in the intestine then circulated in the blood to the liver where it is excreted. A small part of this recirculated urobilinogen is filtered out by the kidneys and appears in urine (less than 1 mg/dl urine). The stercobilinogen can not be reabsorbed and remains in the intestine.[15][16]

Any deterioration in liver function reduces its ability to process the recirculated urobilinogen.[15] The excess that remains in the blood is filtered out by the kidneys and appears in urine. When hemolytic disorders occur the amount of unconjugated bilirubin that is present in the blood increases causing an increase in hepatic excretion of conjugated bilirubin, resulting in increased amounts of urobilinogen that in turn causes an increase in reabsorption, recirculation and renal excretion.[15][16]

The reactions that take place in the test strip vary according to the manufacturer, but in reality there are two reactions that are most frequently used. Some manufacturers use Ehrlich's reaction (1), in which urobilinogen reacts with p-dimethylaminobenzaldehyde (Ehrlich's reagent) in order to produce colours that vary from light to dark pink. Other manufacturers use a diazo coupling reaction (2) that uses 4-methoxybenzene-diazonium-tetrafluoroborate to produce colours that vary from white to pink. The latter reaction is more specific.[17]

  • (1) Reaction on Multistix (in acid medium)

    Urobilinogen + p-dimethylaminobenzaldehide → Red dye

  • (2) Reaction on Chemstrip (in acid medium)

    Urobilinogen + 4-methoxibenzene-diazonium-tetrafluoroborate → Red azo dye

A number of substances interfere with the Ehrlich reaction on the Multistix strip: porphobilinogen, indican, p-amino salicylic acid, sulphonamide, methyldopa, procaine and chlorpromazine. The test should be carried out at room temperature as the reaction's sensitivity increases with temperature. Poorly stored samples can yield false negative results as the urobilinogen suffers photo oxidation to urobilin that does not react. The formaldehyde used as a preservative produces false negatives in both reactions.[16]

Urinary infections[edit]

Urinary infections can be identified including bacteriuria and pyuria.

Nitrites test[edit]

The test for nitrites is a rapid screening method for possible asymptomatic infections caused by nitrate-reducing bacteria. Some of the gram negative bacteria species that most commonly cause urinary tract infections (Escherichia coli, Enterobacter, Klebsiella, Citrobacter and Proteus) have enzymes that reduce the nitrate present in urine to nitrite.[18] The test is a rapid screen for possible infections by enteric bacteria, but it does not replace the urinalysis tests nor microscopic examination as diagnostic tools, nor subsequent monitoring as many other microorganisms that do not reduce nitrate (gram positive bacteria and yeasts) can also cause urinary infections.[19][20]

The reactive strips detect nitrite by using the Griess reaction in which the nitrite reacts in an acid medium with an aromaticamine (para-arsanilic acid or sulphanilamide) in order to form a diazonium salt that in turn reacts with tetrahydrobenzoquinoline to produce a pink azo dye.[6][20]

  • 1) In an acid medium

    Para-arsanilic acid or sulphanilamide + NO
    2 → Diazonium salt

  • 2) In an acid medium

    Diazonium salt + tetrahydrobenzoquinoline → Pink azo dye

The nitrite test is not particularly reliable and negative results in the presence of clinical symptoms are not uncommon, meaning that the test should not be taken as conclusive. Negative results can be obtained in the presence of non nitrate-reducing microorganisms. Nitrite-reducing bacteria need to remain in contact with nitrate for long enough to produce detectable amounts (first urine produced in the morning or at least with a urine retention of 4 hours). Large numbers of bacteria can react to reduce nitrite to nitrogen, which will give a false negative result. The use of antibiotics will inhibit bacterial metabolism causing negative results even though bacteria are present. In addition some substances such as ascorbic acid will compete with the Greiss reaction giving unrepresentatively low readings.[6][20]

Leukocytes test[edit]

A sample of urine sediment from a patient suffering from a urinary infection, it is possible to see leukocytes(small round and granular), erythrocytes(small round and biconcave) and epithelial cells (large and polyhedral). The test for leukocyte esterase is indicative and does not replace microscopic examination of urine.[19]

It is normal to find up to 3 (occasionally 5) leukocytes per high power field (40X) in a urine sample, with women having slightly higher results owing to vaginal contamination.[citation needed] Higher numbers indicate urinary infection. The urine test strip test for white blood cells detects leukocyte esterase, which is present in azurophilic granules of monocytes and granulocytes (neutrophilic, eosinophilic and basophilic). Bacteria, lymphocytes and epithelial cells from the genitourinary tract do not contain esterases.[21] Neutrophil granulocytes are the leukocytes most commonly associated with urinary infections. A positive test for leukocyte esterase normally indicates the presence of bacteria and a positive nitrite test (although it is not always the case). Infections caused by Trichomonas, Chlamydia and yeasts produce leukocyturia without bacteriuria. The inflammation of the renal tissues (interstitial nephritis) can produce leukocyturia, in particular toxic interstitial nephritis with predominant eosinophils.[21]

The test for leukocyte esterase is purely indicative and should not be solely relied on for diagnosis, as it does not replace microscopic or urine culture examinations.[19]

The urine test strip reaction is based on the action of leukocyte esterase in catalysing the hydrolysis of an ester of indolecarboxylic acid. The indoxyl that is liberated combines with a diazonium salt in order to produce a violet coloured azole dye.[21]

  • 1) Reaction catalysed by leukocyte esterase

    Indolecarboxylic acid ester → Indoxyl + Acid

  • 2) In acid medium

    Indoxyl + Diazonium salt → Violet azole dye

The esterase reaction needs about 2 minutes to take place. The presence of strong oxidising agents or formaldehyde can cause false positives. False negative results are associated with elevated concentrations of protein (greater than 500 mg/dL), glucose (greater than 3 g/dL), oxalic acid and ascorbic acid. Urine with a high specific gravity can also cause leukocyte crenation, which can impede the liberation of the esterases.[22]

Detection limit[edit]

The detection limit of a test is the concentration at which the test starts to turn from negative to positive. Although the detection limit may vary between urine samples, the detection limit is defined as the concentration of the analyte that results in a positive reaction in 90% of the examined urines.

Parameter Reference range

- more detailed
ranges in
Urinalysis article

Practical detection limit
Specific Gravity

Reference range

Physiological range

1.016 - 1.022

1.002 - 1.035

Range: 1.000 - 1.030
pH value

First morning urine

During the day

5 - 6

4.8 - 7.4

Range: 5 - 9
Leukocytes

Reference range

Grey zone

< 10 Leu/µl

10 - 20 Leu/µl

10-25 Leu/µl

Nitrite- 0.05 mg/dl (11 µmol/l)
Protein

Albumin

< 2 mg/dl

6 mg/dl

Glucose

First morning urine

During the day

< 20 mg/dl

< 30 mg/dl

40 mg/dl (2.2 mmol/l)

Ketones

Acetoacetic acid

Acetone

< 5 mg/dl

-

5 mg/dl (0.5 mmol/l)

40 mg/dl (7 mmol/l)

Urobilinogen< 1 mg/dl 0.4 mg/dl (7µmol/l)
Bilirubin< 0.2 mg/dl 0.5 mg/dl (9µmol/l)
Blood

Erythrocytes

Haemoglobin

0 - 5 Ery/µl

-

5 Ery/µl

0.03 mg/dl Hb

[23]

Medical uses[edit]

Urine test strips can be used in many areas of the healthcare chain including screening for routine examinations, treatment monitoring, self-monitoring by patients and/or general preventive medicine.

Screening[edit]

Urine test strips are used for screening both in hospitals and in general practice. The aim of screening is early identification of likely patients by examination of large groups of the population. The importance of screening for diabetes and kidney disease amongst high-risk populations is becoming very high.

Treatment monitoring[edit]

Treatment monitoring with the aid of urine test strips allows a health professional to check on the results of the prescribed therapy, and if necessary to introduce any changes into the course of therapy.

Self-monitoring[edit]

Self-monitoring with urine test strips under the guidance of a health professional is an effective method for monitoring the disease state. This applies particularly to diabetics, where the idea of self-monitoring of the metabolic status (determinations of glucose and ketones) is self-evident.

Veterinary[edit]

In veterinary medicine, especially in cats and dogs, the test strip can be used for urinalysis.

History[edit]

In many cultures urine was once regarded as a mystical fluid, and in some cultures it is still regarded as such to this day. Its uses have included wound healing, stimulation of the body's defences, and examinations for diagnosing the presence of diseases.

It was only towards the end of the 18th century that doctors interested in chemistry turned their attention to the scientific basis of urinalysis and to its use in practical medicine.

  • 1797 - Carl Friedrich Gärtner (1772–1850) expressed a wish for an easy way of testing urine for disease at the patient's bedside.[24]
  • 1797 - William Cumberland Cruikshank (1745–1800) described for the first time the property of coagulation on heating, exhibited by many urines.
  • 1827 - English physician Richard Bright describes the clinical symptom of nephritis in “Reports of Medical Cases.”
  • 1840 - The arrival of chemical urine diagnostics aimed at the detection of pathological urine constituents
  • 1850 - Parisian chemist Jules Maumené (1818–1898) develops the first “test strips” when he impregnated a strip of merino wool with “tin protochloride” (stannous chloride). On application of a drop of urine and heating over a candle the strip immediately turned black if the urine contained sugar.
  • 1883 - English physiologist George Oliver (1841–1915) markets his “Urinary Test Papers”
  • approx. 1900 - Reagent papers become commercially obtainable from the chemical company of Helfenberg AG.
  • 1904 - A test for the presence of blood by a wet-chemical method using benzidine became known.
  • approx. 1920 - Viennese chemist Fritz Feigl (1891–1971) publishes his technique of “spot analysis".
  • 1930s - Urine diagnostics makes major progress as reliability improves and test performance becomes progressively easier.
  • 1950s - Urine test strips in the sense used today were first made on industrial scale and offered commercially.
  • 1964 - The company Boehringer Mannheim, today Roche, launched its first Combur test strips.

Even though the test strips have changed little in appearance since the 1960s, they now contain a number of innovations. New impregnation techniques, more stable colour indicators, and the steady improvement in colour gradation have all contributed to the fact that the use of urine test strips has now become established in clinical and general practice as a reliable diagnostic instrument. The parameter menu offered has steadily grown longer in the intervening decades.

Ascorbic acid interference[edit]

Ascorbic acid (vitamin C) is known to interfere with the oxidation reaction of the blood and glucose pad on common urine test strips. Some urine test strips are protected against the interference with iodate, which eliminates ascorbic acid by oxidation.[25] Some test strips include a test for urinary ascorbate.

Urinary sediment[edit]

During routine screening, if a positive test for leukocytes, blood, protein, nitrite, and a pH greater than 7 is identified, the urine sediment be microscopically analysed to further pinpoint a diagnosis.

Automated analysers[edit]

Automatic analysis of urine test strips using automated urine test strip analysers is a well-established practice in modern-day urinalysis. They can measure calcium, blood, glucose, bilirubin, urobilinogen, ketones, leukocytes, creatinine, microalbumin, pH, ascorbic acid and protein.[26]

References[edit]

  1. ^Yetisen A. K. (2013). "Paper-based microfluidic point-of-care diagnostic devices". Lab on a Chip. 13 (12): 2210–2251. doi:10.1039/C3LC50169H. PMID 23652632.
  2. ^ abcdefStrasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 53–76. ISBN . Retrieved March 13, 2012.
  3. ^http://www.seg-social.es/ism/gsanitaria_es/ilustr_capitulo6/cap6_7_analisorina.htm language = Spanish
  4. ^ abcStrasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 56–57. ISBN . Retrieved 13 March 2012.
  5. ^ADW Diabetes.
  6. ^ abcdefghijkBayer Multistix reagent strips
  7. ^Strasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "4". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 46–47. ISBN . Retrieved 14 March 2012.
  8. ^ abcStrasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 75–76. ISBN . Retrieved 14 March 2012.
  9. ^"Urine specific gravity". Medline Plus. Retrieved 30 March 2013.
  10. ^Urinalaysis and Body Fluids Sixth Edition by Susan King Strasinger and Marjorie Schaub Di Lorenzo
  11. ^"Your Kidneys and How They Work". National Kidney and Urological Disease Information Clearing House. 2007. Retrieved 2009-02-17.
  12. ^Urinalysis and Body Fluids by Susan King Strasinger and Marjorie Schaub Di Lorenzo
  13. ^ abcdeWein, Alan J.; Kavoussi, Louis R.; Novick, Andrew C.; Partin, Alan W.; Peters, Craig A. (2007). "3". Campbell-Walsh Urología (in Spanish) (9ª ed.). Editorial Médica Panamericana. pp. 97–98. ISBN . Retrieved 13 March 2012.
  14. ^Tests for the Identification of Aldehydes and Ketones (in Spanish)
  15. ^ abcWein, Alan J.; Kavoussi, Louis R.; Novick, Andrew C.; Partin, Alan W.; Peters, Craig A. (2007). "3". Campbell-Walsh Urología (in Spanish) (9ª ed.). Editorial Médica Panamericana. p. 104. ISBN . Retrieved 13 March 2012.
  16. ^ abcStrasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 70–73. ISBN . Retrieved 14 March 2012.
  17. ^Graff, Laurine (1987). "2". Análisis de orina - Atlas Colour (in Spanish) (1ª ed.). Ed. Médica Panamericana. p. 59. ISBN . Retrieved 14 March 2012.
  18. ^Graff, Laurine (1987). "2". Análisis de orina - Atlas Colour (in Spanish) (1ª ed.). Ed. Médica Panamericana. p. 60. ISBN . Retrieved 14 March 2012.
  19. ^ abcWein, Alan J.; Kavoussi, Louis R.; Novick, Andrew C.; Partin, Alan W.; Peters, Craig A. (2007). "3". Campbell-Walsh Urología (in Spanish) (9ª ed.). Editorial Médica Panamericana. p. 104. ISBN . Retrieved 14 March 2012.
  20. ^ abcStrasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 73–75. ISBN . Retrieved 14 March 2012.
  21. ^ abcStrasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 74–75. ISBN . Retrieved 14 March 2012.
  22. ^Scheer, KA; Segert, LA; Grammers, GL (1984). "Urine leukocyte esterase and nitrite tests as an aid to predict urine culture results". Lab Med. 15 (3): 186–187. doi:10.1093/labmed/15.3.186.
  23. ^(2008) Combur-Test: Detailed information. Retrieved February 09, 2009, from Roche Diagnostics. Web site: http://www.diavant.com/diavant/CMSFront.html?pgid=3,2,14,1
  24. ^Sahnan, Kapil; Blakey, Sarah; Ball, Kathryn; Bagenal, Jessamy; Patel, Biral (January 2013). "I went to the urologist and this is what I brought". Bulletin of the Royal College of Surgeons of England. 95 (1): 43–44. doi:10.1308/147363513x13500508918656.CS1 maint: uses authors parameter (link)
  25. ^Brigden ML, Edgell D, McPherson M, Leadbeater A, Hoag G (March 1992). "High incidence of significant urinary ascorbic acid concentrations in a west coast population—implications for routine urinalysis". Clin. Chem. 38 (3): 426–31. PMID 1547565.
  26. ^"Archived copy". Archived from the original on 2012-06-30. Retrieved 2013-04-02.CS1 maint: archived copy as title (link)

Further reading[edit]

  • Compendium Urinalysis: Urinalysis with Test Strips. Dr E F Hohenberger, Dr H Kimling (2002)http://www.diavant.com/diavant/servlet/MDBOutput?fileId=1392
  • Strasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ª ed.). Editorial panamericana. pp. 56–57. ISBN . Retrieved 14 March 2012.
  • Graff, Laurine (1987). "2". Análisis de orina - Atlas Colour (in Spanish) (1ª ed.). Ed. Médica Panamericana. p. 60. ISBN . Retrieved 14 March 2012.
  • Wein, Alan J.; Kavoussi, Louis R.; Novick, Andrew C.; Partin, Alan W.; Peters, Craig A. (2007). "3". Campbell-Walsh Urología (in Spanish) (9ª ed.). Editorial Médica Panamericana. p. 104. ISBN . Retrieved 14 March 2012.
  • Urinalysis Strips Instructions
Sours: https://en.wikipedia.org/wiki/Urine_test_strip

Results meaning chart test urine strips

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Urinalysis - OSCE Guide

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