II. Background

  1. Bilirubin testing on the Urine Dipstick reflects tests for 2 different related compounds
  2. Conjugated Bilirubin
    1. Unconjugated Bilirubin is not soluble in water and is not found in the urine
    2. Conjugated Bilirubin is excreted in the stool under normal conditions
    3. Conjugated Bilirubin is an abnormal finding in the urine and reflects liver disease (or False Positive)
    4. Ictotest can be run as a confirmatory test for urine Conjugated Bilirubin
  3. Urobilinogen
    1. Relatively small amount of Bilirubin is converted to Urobilinogen in the intestinal tract and renally excreted
    2. Large amounts of Urobilinogen suggest hepatic disease or Hemolysis

III. Causes: Urine Conjugated Bilirubin

  1. True Positive Test
    1. Biliary tract obstruction
    2. Hepatitis
      1. Viral Hepatitis
      2. Toxic Hepatitis
      3. Drug Induced Hepatitis
  2. Confirmatory Findings of Positive Test
    1. Ictotest Positive
    2. Gross urine findings if Conjugated Bilirubin present
      1. Dark Urine with yellow foam
      2. Sediment elements may be stained
  3. False Positive Bilirubin (Ictotest Negative)
    1. Chlorpromazine (Thorazine)
    2. Phenazopyridine (Pyridium)
  4. False Negative Bilirubin
    1. Selenium
    2. Vitamin C
    3. Prolonged light exposure

IV. Causes: Urobilinogen

  1. True Positive Urobilinogen
    1. Trace or Small Urobilinogen may be a normal finding
    2. Hepatitis
    3. Liver disease
      1. Cirrhosis
      2. Liver Metastases
      3. Liver infarction
    4. Hemolytic Jaundice
  2. False Positive Urobilinogen
    1. Phenazopyradine (Pyridium)
    2. Sulfonamides
  3. False Negative Tests
    1. Inadequate urine sample storage
    2. Preservatives present in urine sample

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