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What are White Blood Cells in Urine?

White blood cells (WBCs) in urine, known as pyuria, indicate inflammation or infection somewhere in the urinary tract. In healthy urine, WBCs are minimal—typically 0–5 cells per high-power field (hpf) under a microscope. Elevated counts often signal urinary tract infections (UTIs), kidney infections, stones, or other urinary conditions that require medical evaluation.

Understanding White Blood Cells in Urine

WBCs are part of your immune system’s defense against harmful microorganisms. When bacteria, viruses, or other irritants are detected in the urinary tract, the body dispatches WBCs to fight the threat. Their presence in urine reflects this immune activity and can help pinpoint underlying urinary or kidney problems.

Normal Ranges

  • Normal: 0–5 WBCs/hpf
  • Borderline elevated: 6–10 WBCs/hpf
  • Significantly elevated: >10 WBCs/hpf
  • Severe pyuria: >50 WBCs/hpf

Results above 5 WBCs/hpf generally warrant further investigation, especially if accompanied by urinary symptoms.

Common Causes of Elevated WBCs in Urine

Infections

  • Urinary tract infections (UTIs): Most common cause; symptoms include burning urination, urgency, cloudy urine.
  • Kidney infections (pyelonephritis): Can cause fever, back pain, nausea.
  • Sexually transmitted infections (STIs): Such as chlamydia, gonorrhea, trichomoniasis.

Non-infectious Causes

  • Kidney stones: Irritate urinary tract lining, sometimes with secondary infection.
  • Interstitial cystitis: Chronic bladder inflammation without infection.
  • Prostatitis: Prostate gland inflammation in men.
  • Autoimmune diseases: Lupus and others affecting the kidneys.
  • Urinary tract cancers: Rare but important to rule out.
  • Medication reactions: Certain antibiotics, NSAIDs.

Symptoms That May Accompany Pyuria

  • Painful or burning urination
  • Frequent or urgent urination
  • Cloudy or foul-smelling urine
  • Lower abdominal or back pain
  • Fever and chills
  • General fatigue

Some people, especially older adults or immunocompromised individuals, may have significant pyuria without noticeable symptoms.

Testing and Diagnosis

  • Urinalysis: Chemical dipstick detects leukocyte esterase (WBC enzyme); microscopic exam counts cells.
  • Urine culture: Identifies bacteria and antibiotic sensitivity.
  • Clean-catch midstream collection: Reduces contamination from skin/genital flora.
  • Additional tests: Blood work for kidney function, imaging (ultrasound, CT) for structural issues.

Treatment Approaches

Depends on the cause:

  • Bacterial infections: Antibiotics tailored to culture results.
  • Kidney stones: Hydration, pain control, possible procedures to remove or break stones.
  • Non-infectious inflammation: Symptom management, addressing underlying condition.
  • Prostatitis: Combination of antibiotics, anti-inflammatory medications.

Prevention Strategies

  • Stay hydrated (8+ glasses water/day)
  • Practice good bathroom hygiene (front-to-back wiping)
  • Urinate after sexual activity
  • Avoid irritating hygiene products in genital area
  • Wear breathable cotton underwear
  • Consider cranberry products, probiotics, vitamin C, or D-mannose if prone to UTIs (consult provider first)

When to Seek Care: See a healthcare provider promptly if WBCs in urine are accompanied by fever, severe pain, blood in urine, persistent vomiting, or symptoms lasting more than 48 hours. Early diagnosis and treatment help prevent complications.

DISCLAIMER: THIS INFORMATION IS FOR EDUCATIONAL PURPOSES AND SHOULD NOT REPLACE MEDICAL ADVICE. ALWAYS CONSULT YOUR HEALTHCARE PROVIDER FOR PERSONALIZED CARE.