What does “18 red blood cells per high-power field (HPF) in routine urinalysis” indicate?

Under normal circumstances, a urine routine test showing 18 red blood cells per high-power field (RBC/HP) may result from factors such as intense physical exercise, menstrual contamination, urethritis, cystitis, or ureteral calculi. If associated symptoms are present, prompt consultation and treatment at a reputable hospital are recommended. A detailed analysis follows:

1. Intense Physical Exercise

High-intensity exercise accelerates systemic circulation, causing transient renal congestion and allowing a small number of red blood cells to pass into the urine. Reducing high-intensity activity, replenishing fluids promptly after exercise, and ensuring adequate rest typically restore normal urine routine results upon retesting.

2. Menstrual Contamination

During menstruation, menstrual blood may inadvertently contaminate the urine specimen, leading to falsely elevated RBC counts. To avoid this, urine samples should be collected outside the menstrual period. Prior to collection, the external genitalia should be thoroughly cleansed, and a midstream urine sample should be obtained for testing.

3. Urethritis

Bacterial infection of the urethra induces mucosal inflammation, resulting in mucosal hyperemia and micro-erosions with minor bleeding that mixes into the urine, elevating RBC levels. Treatment may include antibiotics prescribed by a physician—such as levofloxacin tablets, amoxicillin capsules, or norfloxacin capsules—alongside increased fluid intake to maintain urethral patency.

4. Cystitis

Inflammatory changes in the bladder mucosa render it fragile and prone to micro-bleeding, leading to abnormal urinary RBC elevation. Antibiotics such as cefdinir dispersible tablets, fosfomycin trometamol powder, or enteric-coated nitrofurantoin tablets may be prescribed under medical supervision. Additionally, developing a habit of frequent urination and avoiding urinary retention is advised.

5. Ureteral Calculi

Urinary stones cause mechanical irritation and abrasion of the ureteral mucosa, resulting in mucosal injury and bleeding, thereby increasing urinary RBC counts. Medical management may include stone-expelling granules, Lysimachia christinae granules, or tamsulosin sustained-release capsules, as directed by a physician. For larger stones, ureteroscopic lithotripsy and stone extraction may be required; postoperatively, adequate hydration is encouraged to facilitate residual stone passage.

In daily life, maintain adequate daily fluid intake and avoid prolonged urinary retention; practice good perineal hygiene to prevent urinary tract infections; maintain regular sleep-wake cycles and engage in moderate physical activity while minimizing excessive exertion; and undergo routine urinalysis periodically to monitor urinary system health.