Radioimmunoassay for aldosterone in plasma without chromatography.

A radioimmunoassay without chromatography is described for the determination of plasma aldosterone. The high sensitivity of the method renders possible the detection of about 1 pg aldosterone/ml. The high specificity of the antialdosterone sera (rabbit) may be due to the procedure used for the preparation of aldosterone-21-hemisuccinate and to the intensive purification of the aldosterone-albumin conjugate. The validity of the method was tested by determination of plasma aldosterone in normal subjects and in patients suffering from primary hyperaldosteronism or Addison's disease. In cases of urgent diagnosis, the incubation period was reduced from 16 hours to 1 hour. The elimination of the chromatographic step makes the method suitable for clinical routine work and automatization.