A radioimmunoassay of human prealbumin in body fluids

Prealbumin (PA) was purified 35-fold from human serum and antibodies raised against it in rabbits. A 2 hour radioimmunoassay (RIA) using polyethyleneglycol (PEG) to separate bound and free PA was used to determine levels in body fluids. Using patient serum specimens the new method was compared with an electroimmunoassay (EIA) method and the regression equation obtained was: y=1.13x-9.91. The RIA and EIA methods compared favourably with respect to precision to practicability and economy. The RIA method seems especially suitable for large scale assays of PA and is 100 times more sensitive than EIA. Preliminary estimations of PA with the RIA method in plasma, cerebrospinal fluids, amniotic fluids, duodenal juices and urines were carried out. The results indicate that this method can be conveniently used to assay PA in body fluids where the protein is present in low concentration. (Auth.)