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What is Leukocyte Esterase?

What is Leukocyte Esterase?

A complete blood cell (CBC) test often includes a measurement of the level of leukocytes, or white blood cells (WBCs). Higher levels of leukocytes in the bloodstream may indicate an infection. This happens because WBCs are part of the immune system, and they help fight off disease and infection. Leukocytes may also be found in a urinalysis, or a urine test. High levels of WBCs in your urine also suggest that you have an infection. In this case, your body is trying to fight off an infection somewhere in your urinary tract. Generally, that means the bladder or the urethra, which is the tube that carries urine from the bladder. Leukocytes in the urine could also suggest a kidney infection.

What is leukocyte esterase?

The leukocyte esterase is an enzyme that is released by white blood cells (WBCs). Although it is fairly common to have a few WBC in the urine, this will not produce a positive leukocyte esterase test. Any condition that will significantly increase the number of WBCs in the urine will yield a positive result.

What means being tested?

A urinalysis is a group of physical, chemical, and microscopic tests. The tests detect or measure several substances in the urine, such as byproducts of normal and abnormal metabolism, cells, cellular fragments, and bacteria.

Urine is produced by the kidneys, two fist-sized organs located on either side of the spine at the bottom of the ribcage. The kidneys filter wastes out of the blood, help regulate the amount of water in the body, and conserve proteins and other compounds that the body can reuse. Anything that is not needed is eliminated in the urine, traveling from the kidneys through ureters to the bladder and then through the urethra and out of the body. Urine is generally yellow and relatively clear, but each time a person urinates, the color, quantity, concentration, and content of the urine will be slightly different because of varying constituents.

Many disorders may be detected in their early stages by identifying substances that are not normally present in the urine or by measuring abnormal levels of certain substances. Some examples include glucose, protein, bilirubin, white blood cells, crystals, and bacteria.


Leukocytes in urine don’t necessarily cause symptoms on their own. If you do have leukocytes in your urine, your symptoms will vary depending on the condition that is causing the leukocytes to build up in your urine.

The symptoms of a UTI include:

  • a frequent urge to urinate
  • a burning sensation when urinating
  • cloudy or pink-tinted urine
  • pelvic pain, especially in women

The results

A positive leukocyte esterase result means there is pyuria or an increased amount of leukocytes in the urine. This result means that one may have a urinary tract infection. Pathologic conditions such as urethritis and cystitis are also common causes of pyuria. Sexually transmitted infections such as gonorrhea and chlamydia may also increase the WBC in the urine. Further diagnostic tests may be requested following a positive leukocyte esterase result. A urine culture may be performed in order to identify the pathogen that is causing the infection. It is crucial to finish the entire course of treatment to prevent the reoccurrence of the infection.

One of the easiest ways to help keep the urinary tract free of infections or kidney stones is to stay hydrated as much as possible. Drink several glasses of water per day, and talk to your doctor about what amount of water is best for you. If you have a condition such as heart failure, your doctor may recommend that you limit your fluid intake. If you’re active or pregnant, you may need to drink more water every day. Eating cranberries and drinking cranberry juice may help lower your risk of developing UTIs. That is because a substance in cranberries may help protect your bladder and make it more difficult for certain bacteria to stick to your urinary tract.