Evaluation of tests for Gilbert's syndrome.

The effect of caloric restriction (400 kcal for 24 hours) on serum total and unconjugated bilirubin was studied in 30 subjects with Gilbert's syndrome and in 22 patients with different liver diseases. The method could not completely differentiate between Gilbert's syndrome and liver disease, but an increase in unconjugated bilirubin of 15 micromol/l or more supports the former diagnosis. This limit gave a 100% specificity and a sensitivity for males of about 90% and for females of about 40%. I.v. nicotinic acid caused similar rises of unconjugated bilirubin as reduced caloric intake in eight subjects with Gilbert's syndrome, but most of the subjects preferred the latter test. Results from erythrocyte porphyrin determination in seven subjects with Gilbert's syndrome gave some support to the presence of dyserythropoiesis.