American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the maximum bilirubin level typically seen in patients with Gilbert syndrome during fasting?

1. 5 mg/dL

2. 10 mg/dL

3. 3 mg/dL

4. 8 mg/dL

The correct answer is: 3 mg/dL

In Gilbert syndrome, the maximum bilirubin level observed during fasting typically does not exceed 3 mg/dL. Gilbert syndrome is a common, benign genetic condition characterized by mild unconjugated hyperbilirubinemia due to reduced activity of the enzyme UDP-glucuronosyltransferase. This condition often becomes apparent during episodes of fasting, stress, illness, or dehydration, which can lead to transient increases in bilirubin levels. During fasting, the decreased caloric intake can result in a temporary rise in unconjugated bilirubin, but values generally remain within a mild range. Levels exceeding 3 mg/dL are more indicative of other conditions or disorders that lead to more significant bilirubin elevations. Hence, while bilirubin levels can fluctuate, the majority of patients with Gilbert syndrome don't surpass this threshold during fasting periods.