Leukocyte esterase is a urine test to look for white blood cells and other signs of infection.
A clean-catch urine sample is preferred. The clean-catch method is used to prevent germs from the penis or vagina from getting into a urine sample. To collect your urine, the health care provider may give you a special clean-catch kit that contains a cleansing solution and sterile wipes. Follow instructions exactly so that the results are accurate.
After you provide a urine sample, it is tested right away. The provider uses a dipstick made with a color-sensitive pad. The color of the dipstick changes to tell the provider if you have white blood cells in your urine.
No special steps are needed to prepare for this test.
The test will involve only normal urination. There is no discomfort.
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 infection.
A negative test result is normal.
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
An abnormal result indicates a possible urinary tract infection.
The following may turn the test abnormal even when you do not have a urinary infection:
The following may turn the test even when you do have an urinary infection:
Reviewed By: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.