What does a positive bilirubin result on urine dipstick indicate?

• A. Bilirubinuria caused by hemolytic anemia
• B. Positive glucose due to hyperglycemia
• C. Increased bilirubin from liver disease or biliary obstruction.
• D. Normal urobilinogen levels

Answer: (C)

A positive bilirubin result on a urine dipstick signals the presence of conjugated (direct) bilirubin in the urine. Conjugated bilirubin is water-soluble and can appear in urine when the bilirubin that the liver has conjugated is being excreted, typically because of liver disease or biliary obstruction. In these situations the flow of bile is impaired or hepatocytes are unable to properly process bilirubin, allowing conjugated bilirubin to spill into the urine.

This differs from hemolytic anemia, where the problem is an excess of unconjugated (indirect) bilirubin. Unconjugated bilirubin is not water-soluble and is not excreted in urine, so keeping it bound to albumin prevents a positive urine bilirubin dipstick result. Glucose and urobilinogen levels relate to other aspects of metabolism and bile flow, but they do not explain a positive bilirubin dipstick in the way conjugated bilirubin does.

So, a positive dipstick bilirubin most strongly points to increased bilirubin from liver disease or biliary obstruction, rather than from hemolysis or unrelated findings.