Urine analysis

Reference Range

Color Yellow
Clarity/turbidity Clear
pH 4.5-8.0
Specific gravity 1.005-1.025
Glucose <130 mg/d
Ketones None
Nitrites Negative
Leukocyte esterase Negative
Bilirubin Negative
Urobilirubin Small amount (0.5-1mg/dL)
Blood <3 RBCs
Protein <150mg/d
RBCs <2 RBCs/hpf
WBCs <2-5 WBCs/hpf
Squamous epithelial cells <15-20 per hpf
Casts 0-5 hyaline casts/hpf
Crystals Occasionally
Bacteria None
Yeast None


  • Midstream urine specimen should be collected in clean container
  • Women should clean external genitalia before voiding to avoid contamination
  • Urine specimen should be analyzed within 30-60min for accurate results


Gross Visual Examination

  • Clarity/turbidity
    • Determined by substances in urine, including cellular debris, casts, crystals, bacteria, proteinuria, vaginal discharge, sperm

Chemical Examination

  • pH
    • Slightly acidic urine is normal
    • Any acid-base abnormalities affects urinary pH
    • Diet can affect pH
    • Useful in evaluation stones, infection, RTA
      • Stones: alkaline (calcium oxalate/calcium phosphate, magnesium-ammonium phosphate, staghorn) vs acidic (uric acid, cysteine)
      • UTI: proteus and klebsiella produce alkaline urine
  • Specific gravity
    • Represents kidney's ability to concentrate urine; often reflective of hydration status
    • Low values can be seen in patients with impaired urinary concentrating ability (i.e. diabetes insipidus, sickle cell nephropathy, acute tubular necrosis)
    • High values can be due to elevated protein or ketoacids
    • Specific gravity should be considered in detection of pediatric UTI[1]
      • The higher the concentration of the urine, when in the presence of negative LE, the higher the negative predictive value of UTI
      • At threshold of greater than or equal to 5 WBCs per HPF in microscopic UA
  • Nitrite
    • 90% specific but 50% sensitive in detecting gram negative bacteria that converts nitrate to nitrite
    • A positive test suggest bacteria but a negative test cannot rule out UTI
  • Leukocyte Esterase
    • Enzyme within WBC that is released when WBCs lyse
    • 70% sensitive and 50% specific for detecting WBCs (pyuria)
  • Bilirubin
    • Increased urobilirubin associated with excessive hemolysis, liver disease, constipation, intestinal bacterial overgrowth
    • Decreased urobilirubin associated with obstructive biliary disease and severe cholestasis

Microscopic Examination

  • WBCs
    • Elevated WBCs indicate infection, inflammation or contamination
  • Epithelial Cells
    • Generally, 15-20 squamous cells or more indicates contamination
    • Hyaline casts - nonspecific
    • Red cell casts - nearly diagnostic of glomerulonephritis or vasculitis
    • White cell casts - tubulointerstitial nephritis, acute pyelonephritis, renal tuberculosis, vaginal infection
    • Muddy-brown granular casts - diagnostic of acute tubular necrosis
    • Waxy and broad casts - advanced renal failure
    • Fatty casts - nephrotic syndrome
  • Bacteria
    • Generally due to infection or contamination
    • If positive for nitrites, leukocyte esterase and bacteria - highly suggestive of UTI
    • If significant amount of squamous epithelial cells - may indicate contamination
    • Urine culture should be obtained if UTI suspected
      • Generally, >100K/mL of a single organism reflects significant bacteriuria
  • Yeast
    • Generally due to infection or contamination

See Also


  1. Chaudhari PP et al. The Importance of Urine Concentration on the Diagnostic Performance of the Urinalysis for Pediatric Urinary Tract Infection. Ann Emerg Med. 2017 Feb 3. pii: S0196-0644(16)31512-8.