Simplified radioimmunoassay for aldosterone using antisera to aldosterone-gamma-lactone.

A simplified, non-chromatographic method for aldosterone-gamma-lactone (2) radio-immunoassay is described, using a high titer aldosterone-gamma-lactone antibody. This method takes six working hours for completion; the blanks are below the sensitivity of the assay (0-10 pg), and the intra and interassay coefficient of variation is 4.9% and 8.2% respectively. There is no significant variation with different plasma volumes assayed and the plot of added and assayed aldosterone gives a slope of 0.983. The negligible cross reactivity with other steroids and lactones eliminates the problem of interference by these substances.