Gilbert syndrome is a benign condition characterized by mild unconjugated hyperbilirubinemia, which is caused by a congenital decrease in hepatic uridine diphosphate glucuronyl transferase. Patients with Gilbert syndrome have a defect in the ability to conjugate bilirubin, resulting in unconjugated hyperbilirubinemia. The bilirubin level tends to be highest when the patient is fasting or ill but is usually less than 3 mg/dL (51.3 µmol/L