THE EFFECT OF FASTING ON TOTAL SERUM BILIRUBIN CONCENTRATIONS

Thirty-seven healthy volunteers, 19 of whom had consistently elevated total serum bilirubin (TSB) concentrations, took part in an open, rand omised cross-over study to determine the effect of fasting on TSB conc entrations. The study comprised of two treatments. During one treatmen t period volunteers ate a standard supper but fasted for 24 h thereaft er. During the other treatment period volunteers ate a standard supper , snacks, breakfast and lunch. TSB concentrations were measured at reg ular intervals. In both the normal and high bilirubin groups, minimum TSB values were recorded 4 h after the supper. A 24 h fast more than d oubled TSB concentration from baseline values in both the normal and h igh bilirubin groups. A clinically relevant rise in TSB took place aft er 12 h into the fasting period (TSB of 17.3 mu mol 1(-1) in the faste d group vs 14.0 mu mol 1(-1) in the non-fasted group). When designing a clinical trial, selecting volunteers, or judging the tolerance of a new drug, the rise in TSB caused by fasting must therefore be taken in to account, particularly in trials where volunteers or patients fast b efore entering the study.