Abstract
A highly sensitive enzyme immunoassay of conjugated 1β-hydroxycholic acid in heterologous combination was developed using horse radish peroxidase labeled antigen. The assay method was optimized for quantitation in double antibody- coated microtiter plates. The assay had a lower limit of sensitivity of 12.5pg/assay. The cross-reactivity for glyco 1β- hydroxycholic acid was 80.13% and those for conjugated 1β-hydroxychenodeoxycholic and 1β-hydroxydeoxycholic acids ranged from 0.13 to 7.58%. The values in dried blood samples obtained by the present method correlated well with those in radioimmunoassay (r=0.964). Concentrations of conjugated 1β-hydroxycholic acid in dried blood spotted onto filter paper in newborns with congenital biliary atresia (737±264ng/ml) were significantly higher than those of normal newborns (261±190ng/ml).
