Approach to the evaluation of an adult with isolated unconjugated hyperbilirubinemia

LDH: lactate dehydrogenase; RBC: red blood cell.

* The National Institutes of Health maintains a searchable database of drugs, herbal medications, and dietary supplements that have been associated with liver injury. The hyperbilirubinemia induced by drugs or supplements usually resolves within 48 hours after the drug is discontinued.

¶ Laboratory studies that support the diagnosis of hemolysis include low hemoglobin level, an increased reticulocyte count and signs of RBC destruction (increased LDH or low haptoglobin). Evaluation of a peripheral smear can confirm the presence and determine cause of hemolytic anemia. Refer to UpToDate topics on hemolytic anemia.

Δ Patients with hemolysis may also have Gilbert syndrome. This should be suspected in the presence of severe hyperbilirubinemia compared with the degree of hemolysis.

◊ Serum bilirubin levels fluctuate in patients with Gilbert syndrome. They are usually less than 3 mg/dL (51.3 micromol/L) and can be normal. Certain associated pathologic conditions or physiologic events can increase the plasma bilirubin concentrations to higher values, but usually less than 6 mg/dL (102.6 micromol/L).