II. Mechanism

  1. Some Bacteria reduce nitrates to nitrites
  2. Nitrite production typically requires urine standing (in Bladder) for at least 4 hours
    1. Infants do not hold their urine, and do not typically demonstrate nitrite on the urine sample

III. Efficacy

IV. Interpretation

  1. Normal: Negative
  2. Positive
    1. Urinary Tract Infection
    2. Gross Hematuria

V. Causes: False positive nitrite on Urinalysis

  1. Vaginal contaminant
  2. Phenazopyridine
  3. Dipstick exposed to air
    1. Close test strip containers immediately
    2. Strip exposed to air for 1 week: 33% false positive
    3. Strip exposed to air for 2 weeks: 75% false positive

VI. Causes: False negative nitrite on Urinalysis

  1. Increased Urine Specific Gravity
  2. Increased Urobilinogen
  3. Bacteria lacking nitrate reductase enzyme
  4. Urine pH <6.0
  5. Vitamin C supplementation
  6. Low nitrate diet

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