A system for the determination of mineralocorticoid activity by electrical potential difference measurements.

An electronic measuring instrument, which automatically calculates the rectal potential difference, has been developed to determine mineralocorticoid activity in patients with primaroid disorders. A special probe with a disposable tip enables measurements to be made on successive patients without prior cleaning of the probe. The technique, results and their clinical implications are discussed. A highly significant correlation between plasma aldosterone and rectal potential difference is demonstrated.