Leukocytes in urine causes

Leukocytes in urine causes: Description

Leukocyturia is the presence of the white blood cells (WBCs) also called leukocytes in the urine. Pyuria is defined as the presence of the WBCs (namely, neutrophils) or pus in the urine.


Leukocytes (white blood cells) are the main part of the immune system which fight off and protect it from the infection.

In healthy individuals urine is sterile and has only solitary leukocytes (0-5 per high power field). When the amount of WBCs in the urine is abnormal the condition is called leukocyturia/pyuria.  Leukocyturia and pyuria are suggestive of urinary tract or kidney infection. These conditions are characterized by the presence of more than 10 WBCs in 1 mm3 of urine. Pyuria is known as sterile when there are no bacteria in the urine. The urine appears cloudy, dark or brown and may have a strong unpleasant odor.


  • Cystitis (interstitial, radiation) – inflammation of the bladder;
  • Leukocytes in urine causesSexually transmitted diseases;
  • Pyelonephritis;
  • Kidney stones;
  • Polycystic kidney disease;
  • Abnormalities or foreign bodies of the urinary tract;
  • Pelvic inflammatory disease;
  • Bowel incontinence;
  • Pneumonia;
  • Sepsis;
  • Fungal and viral infections;
  • Tuberculosis;
  • Kawasaki disease and other autoimmune disorders;
  • Some medications such as aspirin and paracetamol are known to cause sterile pyuria;

Risk factors

  • Females tend to be at higher risk of both leukocyturia and pyuria;
  • Pregnancy;
  • Menopause;
  • Delayed voiding;
  • Poor hygiene;
  • Large number of sex partners and sexually transmitted diseases;
  • Kidney stones;
  • Abnormalities of the urinary tract;
  • Prolonged use of urinary catheters;
  • Impaired immune system;
  • Diabetes mellitus;
  • History of cystitis or pyelonephritis in the past;


  • Dysuria – painful urination or burning sensation while urinating;
  • Urinary incontinence and strong urge to urinate (urinary urgency), although the bladder may be even empty;
  • Frequent urination of small volumes;
  • Pain above the pubic bone or back pain;
  • Nocturia – frequent urination during the night;
  • Changes in the urine’s color, it may appear dark, brown and cloudy and have a strong, unpleasant odor;
  • Presence of blood in urine (hematuria);
  • Chills, fever;
  • Nausea and/or vomiting;
  • General malaise and fatigue;

Urine microscopy

Normally there are 0-5 leukocytes in urine causes per high power field in the urine sample. WBCs appear as cells with lobed nuclei and granular cytoplasm.

Other investigations

Dipstick test may also be used to detect leukocyturia. A urine culture is required to detect the bacteria which caused the disease. Urinary tract infection may also be confirmed by the presence of nitrates in urine. In some cases cystoscopy, X-ray examination or ultrasound examination CT scan may be needed.