Urine Leukocytes (LEU): What the Test Shows

What are urine leukocytes

Leukocytes (LEU) are white blood cells that are normally found in urine in very small amounts or not at all. An increase in leukocytes in urine is called leukocyturia and most commonly indicates inflammation in the urinary tract.

This marker is determined during a general urinalysis -- using a urine dipstick or microscopy. It is one of the most commonly assessed urine parameters.

Reference ranges

Normal: negative result or up to 5 leukocytes per high-power field (microscopy). A urine dipstick typically shows negative, trace, or positive results.

The reference range provided by your laboratory is always the most important, as methodologies may differ.

Why urine leukocytes may be elevated

An increased leukocyte count in urine most commonly means the body is fighting an infection or inflammation in the urinary tract:

• Urinary tract infection (UTI) -- the most common cause. Bacteria trigger inflammation, and the body sends leukocytes. Usually accompanied by burning, frequent urination, sometimes fever.
• Pyelonephritis (kidney infection) -- a more serious form of UTI where the infection reaches the kidneys. Accompanied by fever, back pain.
• Interstitial nephritis -- kidney inflammation caused by medications or other factors.
• Sexually transmitted infections -- some infections (chlamydia, gonorrhea) can cause leukocyturia.
• Kidney stones -- mechanical damage and inflammation.
• Sterile leukocyturia -- leukocytes are found but no bacteria. May indicate tuberculosis, interstitial nephritis, or atypical infection.

Why the result may be falsely positive

• Vaginal contamination -- if the sample was collected improperly, leukocytes from the vagina may enter the urine.
• Medications -- some drugs may affect the dipstick result.
• Severe dehydration -- highly concentrated urine may sometimes give an imprecise result.

Therefore, it is important to collect the urine sample correctly -- midstream, after hygiene procedures.

What to do next

1. If the dipstick shows positive LEU -- the doctor usually orders a urine culture to identify the specific bacterium. 2. Monitor symptoms: pain, fever, changes in urine color or odor. 3. Drink adequate fluids -- this supports urinary tract hygiene. 4. Repeat the test after treatment to confirm that the inflammation has resolved. 5. If leukocytes are found repeatedly without an obvious cause -- consult a urologist or nephrologist.

Monitoring over time

A single positive result, especially without symptoms, does not always indicate disease. However, recurrent leukocyturia is an important signal.

On the QbiLabs platform, you can track urinalysis results and notice trends, especially if urine tests are done regularly.

Questions for your doctor

• Leukocytes were found in my urine -- is a urine culture needed?
• Could this be related to medications I am taking?
• Leukocytes were found but I have no symptoms -- could this be sterile leukocyturia?
• How often should I repeat the urinalysis?
• Should I consult a urologist?

*This is not medical advice. Consult your doctor for health-related decisions.*