- In hepatic jaundice, conjugated bilirubin decreases along with decreased excre-
tion of bilirubin. The concentration of total bilirubin increases greatly in blood
without any significant change in their ratio. - In posthepatic jaundice (obstructive jaundice), the concentration of conjugated
bilirubin is increased (up to 20 mg/dl) compared to unconjugated bilirubin.
Increased serum bilirubin indicates extrahepatic biliary tract obstruction and
hemolytic diseases.
Total serum bilirubin amount >40 mg/dl indicates hepatocellular obstruction and
not extrahepatic obstruction. Urine bilirubin and urobilinogen are important in
differential diagnosis of jaundice. Bilirubinuria is present in obstructive jaundice
but absent in hemolytic jaundice.
24.7 Clinical Significance 101