D LevelsAreNormalinSubjects withLiverDiseaseand ReducedTotal25-Hydroxyvitamin D Levels

We determined thefreefraction of25-dihydroxyvitamin D (250HD) intheserumofsubjects with clinical evidence ofliver disease andcorrelated these measurements tothelevels ofvitamin Dbinding protein andalbumin. These subjects whencompared tonormal individuals hadlower total 250HDlevels, higher percent free 250HDlevels, butequivalent free 250HDlevels. These subjects also hadreduced vitamin D binding protein and albumin concentrations. Thetotal concentration of250HDcorrelated positively withbothvitamin D binding protein andalbumin, whereas thepercent free 250HDcorrelated negatively withvitamin D binding protein andalbumin. Thefree 250HD levels didnotcorrelate witheither vitamin D binding protein or albumin. Weconclude that total vitamin Dmetabolite measurementsmaybemisleading intheevaluation ofthevitamin D status ofpatients withliver disease, andrecommend that free 250HDlevels also bedetermined before making adiagnosis of vitamin Ddeficiency.