Leukocytes in Urine but No Infection: What Could It Mean?

Yes. Leukocytes are white blood cells, and finding them in urine means there is inflammation or infection somewhere in the urinary tract, or that cells entered the sample from outside it. A urine infection is the most common reason, but contamination, vaginal discharge, sexually transmitted infections and other causes of inflammation can also give a positive result when culture finds no bladder infection.

White cells in urine without bacteria growing on culture is sometimes called sterile pyuria. The name describes a lab pattern, not a diagnosis. This guide explains what the result can and cannot tell you and what to discuss next. If you have UTI symptoms with a negative culture, see the related guide on that situation rather than repeating it here.

A dipstick result matters less than how you feel. Seek urgent medical advice through local services if urinary symptoms come with any of the following. The NHS lists several of these because they can signal a kidney infection, which can lead to sepsis if untreated.

• Confusion, drowsiness or difficulty speaking: call emergency services or go to an emergency department now.
• A very high or low temperature, feeling hot and cold, or shivering.
• Pain in the back just under the ribs, or new lower tummy pain.
• Blood in the urine that looks pink, red or dark brown.
• Symptoms during pregnancy, in a man, in a child, in someone aged 65 or older, or in someone with a urinary catheter, diabetes or a weakened immune system.

Leukocyte esterase is a substance released by white blood cells. The dipstick pad changes colour when it detects it, so a positive result suggests white cells are present. MedlinePlus describes it as a screening test: a negative result is normal, and a positive result indicates a possible urinary tract infection rather than confirming one.

Reports often show the result as negative, trace or a number of plus signs. Cleveland Clinic gives negative or trace as its reference, and up to about 5 white cells per high-power field on microscopy. Laboratories use different methods and reference ranges, so read your result against the range printed on your own report.

A positive dipstick is usually followed by a closer look. MedlinePlus notes that the urine should be examined under a microscope for white cells. A clinician may also send it for culture, which checks whether bacteria actually grow.

Several things can produce white cells in a urine sample, or a positive dipstick, when a bladder infection is not found. The sources below describe these possibilities; only a clinician who knows your history can judge which ones apply.

• Contamination: cells and germs from the skin or genitals can enter the sample. Cleveland Clinic notes this is especially likely for people with a vagina, and squamous epithelial cells on the report can hint at it.
• Vaginal secretions: MedlinePlus lists blood or heavy mucus discharge as a cause of a positive test without a urinary infection.
• Sexually transmitted infections: MedlinePlus lists trichomonas infection. CDC guidance uses a positive leukocyte esterase test on first-void urine as one sign of urethritis, which is often caused by chlamydia or gonorrhoea.
• Inflammation elsewhere in the urinary tract: Cleveland Clinic says more white cells can mean infection or inflammation somewhere along the tract. Clinicians may consider problems such as kidney stones, which urinalysis and imaging help assess.
• Medicines and supplements: Cleveland Clinic notes that some, such as vitamin C, can affect urinalysis results. Mention everything you take, including any recent antibiotic course.

Contamination is one of the most common practical questions. A clean-catch, midstream sample is preferred because it reduces germs and cells from the penis or vagina entering the container. Wash your hands, avoid touching the inside of the pot, pass the first part of the stream into the toilet and collect the middle part.

UK primary care guidance adds that holding the labia apart may help reduce contamination, and that antiseptic should not be used to clean before collecting because it may stop bacteria growing. Tell the clinician if you had a period, vaginal discharge or bleeding when the sample was taken. If contamination is likely, a repeat sample collected carefully may be more useful than acting on the first result.

Not automatically. A standard urinalysis and urine culture are not designed to detect chlamydia, gonorrhoea or trichomonas. These need specific tests, often a urine sample or swab tested by a method called NAAT. CDC treatment guidelines recommend these tests when urethritis is suspected.

UK guidance also asks clinicians to take a sexual history and consider urethritis when someone has urinary symptoms. If there is any chance of an STI, say so; it can change which tests are useful. Burning when passing urine, discharge or pelvic pain are worth mentioning even if they seem minor.

The next step depends on your symptoms, age, pregnancy status and the rest of the result. For women under 65 with urinary symptoms, UK primary care guidance says that leukocytes with a negative nitrite make a UTI equally likely to other diagnoses, and recommends sending urine for culture. The same guidance advises against relying on dipsticks for adults over 65 or people with a catheter.

If white cells persist on repeat tests and no cause is clear, a clinician may consider further tests such as STI testing, kidney blood tests or imaging. Visible or dipstick blood alongside leukocytes is covered in a separate guide on blood in urine.

Take the full report, not just the dipstick summary, and use these questions to clarify the plan.

• Was my sample a clean catch, and could contamination explain the result?
• Was the urine looked at under a microscope or sent for culture, and what did each show?
• Do I need tests for sexually transmitted infections, or other tests the urinalysis does not cover?
• Could any medicine, supplement or recent antibiotic have affected the result?
• Should I repeat the test, and how should I collect the next sample?
• Which new symptoms should make me seek care before the planned follow-up?

On SameCase, patients and verified doctors share de-identified cases. Reading how others with a similar urine result described their symptoms, sample collection and follow-up tests can help you notice details worth mentioning and shape your own questions. Other people's cases cannot tell you what your result means. Use them to prepare, and bring your questions to the clinician who has your full results.