• Young otherwise healthy woman with short course of nausea and diarrhea has persistent indirect hyperbilirubinemia on exam with otherwise normal LFTs, most consistent with Gilbert’s syndrome (deficiency of serum glucuronosyltransferase such that you cannot efficiently conjugate bilirubin)
• Key idea: Prevalence of Gilbert’s syndrome is ~5-10%

https://step-prep.org

Yes, this is Gilbert syndrome. Here's my beef with this question: UDP-glucuronosyltransferase is a liver enzyme. Conjugation takes place in the liver, not the serum.

Here's how you can diagnose Gilbert syndrome according to UTD: "A reduction in hepatic bilirubin-UGT activity, which is approximately 30 percent of normal" https://www.uptodate.com/contents/gilbert-syndrome-and-unconjugated-hyperbilirubinemia-due-to-bilirubin-overproduction

Here's a picture from UTD of the enzyme sitting HAPPILY WITHIN THE HEPATOCYTE: https://www.uptodate.com/contents/image?imageKey=GAST%2F52393&topicKey=GAST%2F3578&search=gilbert%20syndrome&rank=1~53&source=see_link

So how is this a "deficiency of serum glucuronosyltransferase"?

Meanwhile, according to FA2020 p394, Gilbert syndrome also causes "impaired bilirubin uptake." Aka "Impaired hepatic storage of serum bilirubin"

My rage knows no bounds.