A urinalysis dipstick test indicated that urobilinogen was absent. Which condition does this support?

• A. Biliary obstruction
• B. Hepatitis A acute infection
• C. Defective liver cell function
• D. Hepatocellular disease

Answer: (A)

Urobilinogen in urine comes from bilirubin that reaches the gut and is converted by bacteria into urobilinogen, which is then reabsorbed and excreted in urine. When bile flow is blocked, conjugated bilirubin cannot reach the intestine, so less substrate is available for gut bacteria to make urobilinogen. The result is little to no urobilinogen appearing in urine, so its absence supports biliary obstruction.

In acute hepatitis or hepatocellular disease, the problem is hepatocyte injury and altered bilirubin processing, not a complete stoppage of bile reaching the gut, so urobilinogen in urine is not characteristically absent.