Detection of Gilbert's Syndrome in Patients with Hemolysis

Patients with Gilbert's syndrome have a characteristically abnormal pattern of radiobilirubin kinetics. Some patients with hemolysis have a similar abnormality. Demonstration of the Gilbert's type of hepatic defect in such patients previously has required the use of radiobilirubin clearance studies, which are not readily available. Accordingly, we have derived an equation that expresses the predicted range for the plasma concentration of unconjugated bilirubin, in patients with normal hepatic bilirubin clearance, as a function of the total red-cell volume and red-cell half-life, both of which may be determined from a single injection of chromium-51. This equation permits recognition—from radiochromium studies alone—of those patients who have both hemolysis and Gilbert's syndrome, since in such patients the plasma concentration of unconjugated bilirubin will exceed the predicted limits.