Which laboratory abnormality is commonly elevated in liver dysfunction?

• A. Albumin
• B. Bilirubin
• C. INR
• D. Ammonia

Answer: (B)

Bilirubin rises in liver dysfunction because the liver’s ability to conjugate and excrete bilirubin is impaired. When red blood cells break down, bilirubin is formed and travels to the liver bound to albumin. The liver normally conjugates bilirubin, making it water-soluble so it can be excreted in bile. If hepatocytes are damaged or bile flow is obstructed, conjugation and excretion slow or stop, allowing bilirubin to accumulate in the blood. This is why bilirubin elevation is a common and direct indicator of impaired liver function and often presents with jaundice. Other changes can occur in liver disease—albumin synthesis tends to fall, INR can prolong, and ammonia may rise—but the classic lab abnormality tied to the liver’s processing and excretion of bilirubin is the elevated bilirubin level.