Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (743 page)

   Direct bilirubin:

   Twenty to forty percent of total: more suggestive of hepatic than of posthepatic jaundice

   Forty to sixty percent of 1: occurs in either hepatic or in posthepatic jaundice

   Greater than 50% of total: more suggestive of posthepatic than of hepatic jaundice

   Total serum bilirubin >40 mg/dL indicates hepatocellular rather than extrahepatic obstruction.

   Increased unconjugated (indirect) bilirubin in (conjugated, 20% of total)

   Increased bilirubin production.

   Hemolytic diseases (e.g., hemoglobinopathies, RBC enzyme deficiencies, DIC, autoimmune hemolysis).

   Ineffective erythropoiesis (e.g., pernicious anemia).

   Blood transfusions.

   Hematomas.

   Hereditary disorders (e.g., Gilbert disease, Crigler-Najjar syndrome).

   Drugs (e.g., causing hemolysis).