Hyperbilirubinemia of Fasting

The effect of a 44- to 48-hour fast on the serum bilirubin concentration was studied in five normal subjects and in five patients with hepatic dysfunction. The total serum bilirubin (TSB) concentration increased progressively during the fasting period in all patients; expressed as a percent of the control value, it averaged 240% for the normal subjects and 194% for the patients with hepatic dysfunction at the completion of the fast (P>0.05). One normal subject fasted for 110 hours; the TSB increased to 326% of the control value at 63 hours and then fell to approximately twice the control value for the remainder of the fast. A diurnal rhythm of the TSB was demonstrated in one patient, but was suppressed by nocturnal feedings. It was concluded that an increase in bilirubin concentration occurs as a function of fasting.