Aldosterone 18-glucuronide excretion determined with and without chromatography in human hypertensives

24 h-urine excretion of aldosterone-18-glucuronide was determined with and without preceding paper chromatography in patients with essential hypertension (n = 50). Radioimmunoassay was performed with a highly specific antibody against aldosterone. Urine specimens determined without chromatography gave significantly higher values than aliquots which were estimated at the same time with chromatography. A highly significant correlation was found between the two methods (r = 0.91, p less than 0.0001). Without chromatography, mean over estimation in samples with concentrations in the low and middle range was on average 32 and 24% respectively, whereas aldosterone concentrations in the upper range showed a 14% over estimation. The RIA procedure for aldosterone without chromatography as here described is suitable for hypertension screening programmes to exclude known forms of primary hyperaldosteronism in which elevated aldosterone excretion rates have to be differentiated from values lying within the normal range.