If leukocyte esterase is detected, a color change occurs on the reagent pad after the strip is dipped in the urine sample. Be sure to follow the manufacturer's directions for read-time and test interpretation.
A positive leukocyte esterase test indicates the presence of granulocytic white blood cells. Lymphocytes do not contain granules, and would not produce a positive leukocyte esterase test.
Positive results should be confirmed by performing a microscopic examination on the sediment; being aware that white blood cells may be absent if they are lysed, yet releasing their esterases into the specimen. Positive results may occasionally be found in random specimens from females due to contamination of the specimen by vaginal discharge.
