What Causes an Elevated White Blood Cell Count in a Routine Urinalysis?
Jan 15, 2022
Source: Cainiu Health
Dr. Zhang Junfeng
Introduction
Urinary tract infections (UTIs) are categorized into upper and lower UTIs. Upper UTIs primarily involve pyelonephritis, which can be either acute or chronic. Acute pyelonephritis is typically associated with elevated urinary white blood cells (pyuria) and may even present with hematuria (red blood cells in the urine). Thus, isolated elevation of urinary white blood cells may suggest pyelonephritis.
This situation often indicates a urinary tract infection (UTI), which encompasses both upper and lower urinary tract infections. Upper UTIs primarily involve pyelonephritis—either acute or chronic. Acute pyelonephritis typically presents with elevated urinary white blood cells (WBCs) and may even show hematuria (red blood cells in urine). Therefore, isolated elevation of urinary WBCs alone is not highly suggestive of pyelonephritis (i.e., upper UTI). However, if red blood cells are also present, upper UTI cannot be ruled out.
What Causes Elevated White Blood Cell Count in Urinalysis?
Lower urinary tract infections—including cystitis and urethritis—can also cause elevated urinary WBCs. Additionally, certain chronic, specific infections—such as genitourinary tuberculosis—may similarly result in increased urinary WBCs.
Another possibility is asymptomatic urinary abnormality: the patient exhibits no clinical symptoms, yet urinalysis reveals elevated WBCs. This condition is termed “asymptomatic urinary abnormality” and is commonly associated with latent glomerulonephritis. Furthermore, a mildly elevated urinary WBC count may stem from specimen contamination—for instance, vaginal discharge in women can contaminate urine samples and falsely elevate WBC counts. Thus, physiologic causes must always be considered and excluded.
Treatment for elevated urinary WBCs begins with establishing a definitive diagnosis to identify the underlying cause. Once confirmed, comprehensive management is initiated. For UTIs, antibiotics are indicated; levofloxacin is commonly used empirically. However, the most effective approach is to collect a clean-catch midstream urine sample for bacterial culture and antibiotic sensitivity testing prior to initiating empirical therapy—this ensures selection of the most appropriate, pathogen-targeted antibiotic.
Dietary and lifestyle considerations are crucial when urinary WBCs are elevated. Key recommendations include abstaining from smoking and alcohol, increasing fluid intake (especially water), ensuring adequate rest, and engaging in moderate physical activity. Notably, increased hydration is particularly important. For cases where elevated urinary WBCs arise from physiologic factors, proper collection technique is essential: women should avoid urine sampling during menstruation.
We hope the above information is helpful. Wishing you good health and happiness!
