Leukocytes in Urine: What This Urinalysis Result Means

This part of a urinalysis (UA) screens for leukocytes, the white blood cells of your immune system, in your urine. A dipstick detects an enzyme they release, and a laboratory can confirm and count them under the microscope.

White blood cells in the urine are normally absent or very few. When more appear, it usually means there is inflammation somewhere in the urinary tract, most often a urinary tract infection. The result is read together with nitrite and the rest of the panel, because the combination points more clearly to infection than either value alone.

White cells in the urine are not the same as leukocytes in the blood, which reflect your immune system as a whole.

Leukocytes in the urine are a useful early signal because they can appear before symptoms are obvious. In a urinary tract infection they often rise together with nitrite and with bacteria seen under the microscope.

Not every positive result means an infection that needs treatment. White cells can also appear after intense exercise, with a kidney stone, or when a sample is contaminated. Sometimes white cells are present without any bacteria growing, which is called sterile pyuria and has its own list of causes.

Because of this, a positive dipstick is usually confirmed with a urine culture before antibiotics are considered, especially when there are no clear complaints.

A urinalysis with leukocytes is typically requested when a urinary tract infection is suspected, for example with burning during urination, a frequent urge, or lower abdominal or back pain. It is also used as a general screen during a check-up.

A clean-catch midstream sample gives the most reliable result, because it reduces cells and bacteria from the skin around the opening. When the result is unclear or keeps coming back positive, your doctor may add a urine culture to identify the exact bacterium.