Potential Interferences in Urine Dipstick Analysis

FALSE +

FALSE -

Glucose

  • oxidizing cleansers (bleach)
  • ascorbic acid in the urine > 50 mg/dL
  • elevated specific gravity

Bilirubin

  • drugs that color urine red
  • iodine metabolites
  • ascorbic acid in the urine of > 25 mg/dL
  • elevated nitrite
  • prolonged storage and exposure to direct sunlight

Leukocyte Esterase

  • abnormal urine color (red)
  • preservatives
  • contamination due to vaginal discharge
  • tetracycline, cephalexin, oxalic acid
  • elevated glucose
  • elevated specific gravity
  • large protein

Nitrite

  • abnormal urine color
  • ascorbic acid in the urine > 25 mg/dL
  • shorten bladder incubation
  • absence of dietary nitrates

Protein

  • pH > 9.0
  • disinfectants
  • phenazopyridine
  • blood subsitute infusion
  • protein other than albumin

Ketones

  • levodopa metabolites
  • pigmented urines (red/orange)
  • sulfhydryl/mesna compounds

 

Blood

  • oxidizing cleansers (bleach)
  • microbial peroxidase
  • proteinuria (> 500 mg/dl)
  • high specific gravity
  • Capoten

Urobilinogen

  • phenazopyridine
  • formalin preservatives
  • prolonged storage and exposure to direct sunlight

Specific Gravity

  • elevated protein
  • Ketoacidosis
  • elevated pH
  • elevated glucose