What Are the Reasons for High White Blood Cell Count in Urine Tests? How to Address It?

When we become ill and undergo hospital checkups, routine blood tests, urine tests, and stool tests are generally performed. Among these, the urine test is the most common. Frequently, when we receive our urine test reports, we may notice an indication of a high white blood cell (WBC) count. A high WBC count in the urine indicates the presence of inflammation in the body, typically caused by urinary tract infections, bladder infections, kidney infections, or other related infections, leading to such test results.

I. Reasons for High WBC Count in Urine Tests

1. Normally, WBCs are present in the blood. However, due to certain reasons, some WBCs may mix into the urine, resulting in a high WBC count. A small number of WBCs in normal urine is considered normal, with 1-2 WBCs per high-power field (HP) under a microscope. If the count exceeds 5 WBCs per HP, it is referred to as pyuria. The WBCs in urine are mostly neutrophils that appear during inflammatory infections. They undergo degenerative changes, exhibiting irregular shapes and fuzzy structures, also known as pus cells. A high WBC count in urine may also be due to contamination of the sample, such as the introduction of bacteria during urine collection, especially in women, where vaginal discharge may contaminate the sample. Therefore, it is generally recommended to collect midstream urine for testing.

2. If the high WBC count is not due to contamination, the most common cause is urinary tract infection. For instance, infections of the urethra and bladder can manifest as symptoms of frequent urination, urgency, and pain during urination. Pyelonephritis, an infection of the kidney, can also lead to a high WBC count in the urine, accompanied by symptoms such as back pain and fever. The presence of WBC casts in the urine can aid in the diagnosis of pyelonephritis.

3. Apart from infections, conditions such as tuberculosis, kidney stones, foreign bodies, tumors, glomerulonephritis, and tubulointerstitial diseases can also cause leukocyturia. Therefore, it is essential to conduct a thorough analysis of leukocyturia in clinical settings, rather than simply attributing it to urinary tract infections. For instance, the presence of red blood cells and symptoms of back pain may indicate the possibility of urinary stones.

II. What to Do if the Urine Test Shows a High WBC Count

If a high WBC count is detected in a urine test, it is advisable to observe whether there are symptoms of urinary irritation. If there are no symptoms and the high WBC count is only discovered during a routine checkup, it is recommended to collect morning urine for a retest the following day. If the retest still shows a high WBC count, it may indicate asymptomatic bacteriuria, which may require regular monitoring without immediate treatment. However, if symptoms such as frequent urination or urgency are present, it may indicate a urinary tract infection, and appropriate treatment should be administered under a doctor's guidance.