Evaluation of a new commercial radioassay kit for aldosterone using an iodinated tracer

We have evaluated a new non-chromatographic commercial radioimmunoassay kit for serum, plasma, and urine aldosterone levels which employs 125 iodine as the tracer. Within-run and run-to-run precision data show coefficients of variation of 3 to 6% and 8 to 16%, respectively. Recovery of aldosterone added to serum and urine at several levels range from 92 to 109%. Antibody specificity was tested with six structurally related steroids at grossly elevated concentrations and no crossreactivity was observed. Serum or plasma can be used interchangeably in the assay, and normal levels correspond to generally accepted values.