Measurement of Aldosterone in Blood

A detailed method for measuring aldosterone in serum/plasma is described. Aldosterone is first extracted into dichloromethane to improve the specificity of the assay. A radioimmunoassay is performed on the dried extract using an antibody raised in rabbits to aldosterone conjugated at position C3, and iodinated aldosterone. Details are given for optimizing conditions for the second antibody, raised to rabbit immunoglobulins, and carrier protein used in the separation of the antibody bound fraction from the free aldosterone at the end of equilibration. Details are provided in additional notes, for steps in the assay that could be problematic.