Urine tests can sometimes give false results, meaning they show a problem when there isn't actually one and similarly do not correctly determine a problem when there is one. This can happen for different reasons, such as if the urine is too old or if certain substances or medications are present. Also, if the test is not used properly or if the urine container is not sterile or properly cleaned, it can also give false results. 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]

Individual wrapping of Urinox test strips ensures that each urinalysis strip is fresh and not altered by atmospheric conditions so that you get a reliable result every time. This also allows urine test strips to have a shelf life of 24 months from the manufacturing date. Most conventional urinalysis products have a brief shelf life of 30-60 days after opening the bottle. Individual wrapping of strips has various benefits, including less strip wastage, portability for travel, and storage convenience.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] Please repeat the test at different times of the day or on different days to see if you get similar findings. 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 500mg/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 ]

Granulomatosis with polyangiitis: An autoimmune disease that causes the inflammation of blood vessels throughout the body Xu R, Sun S, Huo Y, Yun L, Huang S, Li G, Yan S. Effects of ACEIs versus ARBs on proteinuria or albuminuria in primary hypertension: a meta-analysis of randomized trials. Medicine (Baltimore). 2015;94(39):e1560. doi:10.1097/MD.0000000000001560Satirapoj B, Promrattanakun A, Supasyndh, Choovichian P. The effects of simvastatin on proteinuria and renal function in patients with chronic kidney disease. Int J Nephrol. 2015;2015:485839. doi:10.1155/2015/485839 A swollen abdomen is sometimes known as a distended abdomen or swollen belly. A swollen abdomen is often uncomfortable or even painful, but it’s a… READ MORE 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 ] Strasinger, Susan K.; Di Lorenzo Schaub, Marjorie (2008). "5". Análisis de orina y de los líquidos corporales (in Spanish) (5ªed.). Editorial panamericana. pp.56–57. ISBN 978-950-06-1938-7 . Retrieved 14 March 2012. 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.

While the test kit manufacturer will provide information to help you interpret these results, it’s important to report any atypical test numbers to your doctor right away. The haem fraction of these proteins is toxic for the kidney tubules and elevated concentrations can cause acute kidney injury.For example, if you’re testing your urine’s bilirubin content, you may only need to wait 30 seconds to get test results. However, if you’re testing for blood or nitrites in the urine, you may need to wait 60 seconds. 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 1mg/dL urine). The stercobilinogen can not be reabsorbed and remains in the intestine. [15] [16] approx. 1920 - Viennese chemist Fritz Feigl (1891–1971) publishes his technique of “ spot analysis".