II. Background
- Bilirubin testing on the Urine Dipstick reflects tests for 2 different related compounds
-
Conjugated Bilirubin
- Unconjugated Bilirubin is not soluble in water and is not found in the urine
- Conjugated Bilirubin is excreted in the stool under normal conditions
- Conjugated Bilirubin is an abnormal finding in the urine and reflects liver disease (or False Positive)
- Ictotest can be run as a confirmatory test for urine Conjugated Bilirubin
- Urobilinogen
III. Causes: Urine Conjugated Bilirubin
- True Positive Test
- Biliary tract obstruction
- Hepatitis
- Viral Hepatitis
- Toxic Hepatitis
- Drug Induced Hepatitis
- Confirmatory Findings of Positive Test
- Ictotest Positive
- Gross urine findings if Conjugated Bilirubin present
- Dark Urine with yellow foam
- Sediment elements may be stained
-
False Positive
Bilirubin (Ictotest Negative)
- Chlorpromazine (Thorazine)
- Phenazopyridine (Pyridium)
- False Negative Bilirubin
IV. Causes: Urobilinogen
- True Positive Urobilinogen
- Trace or Small Urobilinogen may be a normal finding
- Hepatitis
- Liver disease
- Hemolytic Jaundice
-
False Positive Urobilinogen
- Phenazopyradine (Pyridium)
- Sulfonamides
-
False Negative Tests
- Inadequate urine sample storage
- Preservatives present in urine sample