Leukocyte esterase

Overview
Leukocyte esterase (LE) is a urine test for the presence of white blood cells and other abnormalities associated with infection.

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. The combination of the LE test with the urinary nitrite test provides an excellent screen for predicting a urinary tract infection. A urine sample that tests positive for both nitrate and leukocyte esterase should be cultured for pathogenic bacteria.