It is an enzyme that is released by white blood cells.
White blood cells in the urine usually indicate a urinary tract infection. The leukocyte esterase (LE) test detects esterase, an enzyme released by white blood cells. Positive test results are clinically significant. The LE test is also used to screen for gonorrhea and for amniotic fluid infections. Leukocyte esterase is a urine test to look for white blood cells and other signs associated with infection. Leukocyte esterase is a screening test used to detect a substance that suggests there are white blood cells in the urine. This may mean you have a urinary tract infection. If this test is positive, the urine should be examined under a microscope for white blood cells and other signs that point to an Leukocyte esterase is a urine test to look for white blood cells and other signs associated with infection. Why the Test is Performed. Leukocyte esterase is a screening test used to detect a substance that suggests there are white blood cells in the urine, which may mean you have a urinary tract A positive finding of the enzyme leukocyte esterase in urinalysis indicates the presence of white blood cells in the urine. This normally suggests inflammation of some sort, often from a urinary tract infection. Causes of Positive Results. Although a urinary tract infection is the most common cause of leukocyte esterase in urinalysis some other and rarer causes for the positive result with a negative microorganism culture do exist. [2] These include: 1  Chlamydia. 2  Infection with a sexually transmitted microorganism called ureaplasma urealyticum The WBC esterase can be a sign of a urinary tract infection. It is an enzyme that is released by white blood cells. Your urinalysis did show that you had some epithelial cells, so it was not a great specimen (not a good clean catch) and was contaminated with some vaginal skin cells.  Leukocyte esterase (LE) is a urine test for the presence of white blood cells and other abnormalities associated with infection. The leukocyte esterase (LE) test detects esterase, an enzyme released by white blood cells. Positive test results are clinically significant. The LE test is also used to screen for gonorrhea and for amniotic fluid infections. Hi dlmiller, Well Leucocyte esterase is a test to check for white blood cells in the urine. When there is a urinary tract infection the wbcs, release leucocyte esterase. Most of the time the nitrate test will also be positive and this really indicates you have a UTI or upper urinary tract infection.  Mobile Questions and Answers. What does it mean if my wbc ur is 10 and my leukocyte esterase ur is moderate. Leukocyte esterase is a urine test to look for white blood cells and other signs associated with infection. What does it mean if i have wbc ur 10. WBC in urine upto 3-5 is normal. More than that may indicate some infection but as you said leukocyte esterase is negative so you can relax. 
https://en.wikipedia.org/wiki/Leukocyte_esterase http://umm.edu/health/medical/ency/articles/leukocyte-esterase https://www.vidanthealth.com/ADAM/HIE%20MultiMedia/1/003584.htm http://www.brighthub.com/science/medical/articles/71126.aspx http://www.justanswer.com/health/2rbk4-does-wbc-esterase-1-abnormal-mean.html https://en.wikipedia.org/wiki/Leukocyte_esterase http://www.medhelp.org/posts/General-Health/1-WBC-Esterase-with-a-negitive-for-UTI-/show/1555039 http://www.healthcaremagic.com/search/what-does-wbc-esterase-mean
what is wbc esterase