In obstructive jaundice, which form of bilirubin tends to accumulate in the blood?

• A. In obstructive jaundice, conjugated (direct) bilirubin accumulates in the blood.
• B. In obstructive jaundice, unconjugated bilirubin accumulates.
• C. No bilirubin accumulates in obstructive jaundice.
• D. Both conjugated and unconjugated bilirubin are cleared normally.

Answer: (A)

When bile flow is blocked, the bilirubin that has already been conjugated in the liver cannot reach the intestine. Conjugated (direct) bilirubin is water-soluble and normally leaves the liver into bile, so with obstruction it backs up into the blood, causing conjugated hyperbilirubinemia. Unconjugated bilirubin, which is not water-soluble and is carried in the bloodstream bound to albumin, is not the primary form that accumulates in obstructive jaundice. So the form that tends to accumulate in the blood is the conjugated (direct) bilirubin.