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Leukocytes (esterase)

Leukocyte esterase is a specific leukocyte (white blood cell) protein. The leukocyte esterase test is used to quickly determine whether there is a significant number of leukocytes in the urine. The leukocyte esterase test detects intact or broken leukocytes. Therefore, it might not be possible to confirm the test under a microscope when overly diluted urine (density less than 1.006) causes the leukocytes to burst. Leukocytes are abundant in vaginal secretions, and specimen contamination is frequent.

A positive urine leukocyte esterase test indicates either a low urinary tract (bladder and urethra) infection or specimen contamination. The chances of it being a urinary tract infection over a specimen contamination are greatly increased if the person presents the appropriate symptoms and their nitrite test is also positive. A positive leukocyte esterase test can also be seen in the absence of bacterial infection in the case of chronic interstitial nephritis, as caused by a kidney stone (lithiasis), a tumour of the bladder or urethra, a severe bladder infection (cystitis), other inflammation processes or in the presence of atypical infections (chlamydia, ureaplasma, tuberculosis).

Term of the Week

Hot zone

A hot zone is a section of a facility (sometimes an entire facility or even a city district) where there is a high risk of contamination by patients with an infectious disease. All individuals entering a hot zone must respect appropriate protective measures. By analogy, “cold zone” and “warm zone” are used to refer to areas where there is no infected individual or only individuals suspected of having an infection.