0.5 mL serum in red top or serum separator tube (labeled as POST).
Test Description
Interferences: Marked hemolysis or lipemia.
Note: Ursodeoxycholic acid may be detected by bile acid assay, causing falsely elevated values. Feed the patient a maintenance diet meal after a 10-12 hour fast and draw a serum sample 2-hours post-feeding. Label the tube as postprandial bile acids.