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Leukocyte esterase urine test


Definition:

Leukocyte esterase is a urine test to look for white blood cells and other signs associated with infection.

Alternative Names:

WBC esterase

How the test is performed:

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 health care provider uses a dipstick made with a color-sensitive pad. The color of the dipstick changes to tell the provider if you may have white blood cells in your urine.

How to prepare for the test:

No special preparation is necessary for this test.

How the test will feel:

The test will involve only normal urination. There is no discomfort.

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. 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.

Normal Values:

A negative test result is normal.

Normal values vary from lab to lab. Talk to your doctor about the meaning of your specific test result.

The following may create a false positive result:

  • Trichomonas infection (such as trichomoniasis)
  • Vaginal secretions (such as blood or heavy mucus discharge)

False negative tests can be caused by:

  • High level of protein
  • High level of vitamin C
What abnormal results mean:

An abnormal result indicates a possible urinary tract infection.

Special considerations:
 
References:

Gerber GS, Brendler CB. Evaluation of the urologic patient: history, physical examination, and urinalysis. In: Wein AJ, Kavoussi LR, Novick AC, et al., eds. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 3.

McPherson RA, Ben-Ezra J. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 28.


Review Date: 8/18/2013
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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