Endocrine Abstracts (2017) 49 GP14 | DOI: 10.1530/endoabs.49.GP14

Simultaneous assays of aldosterone and renin concentrations in just ten minutes could change the clinical assessment for the diagnosis of primary aldosteronism

Fumitoshi Satoh1,2, Morimoto Ryo2, Yoshikiyo Ono2, Yuta Tezuka1,2, Kei Omata1,2, Masahiro Nezu2, Yoshitsugu Iwakura2, Yoshuhiro Igarashi2, Masataka Kudo2 & Sadayoshi Ito2

1Tohoku University Graduate School of Medicine – Division of Clinical Hypertension, Endocrinology and Metabolism, Sendai, Japan; 2Tohoku University Hospital – Division of Nephrology, Endocrinology and Vascular Medicine, Sendai, Japan.

Measurement of plasma aldosterone and renin concentration, or activity, is useful for selecting antihypertensive agents as well as detecting hyperaldosteronism in hypertensive patients. However, it takes several days to get results when measured by radioimmunoassay and development of more rapid assays has been long expected. We have developed chemiluminescent enzyme immunoassays enabling the simultaneous measurement of both aldosterone and renin concentrations in ten-minutes by a fully automated assay using antibody-immobilized magnetic particles with quick aggregation and dispersion. We performed clinical validation of diagnostic ability of this newly developed assay-based screening of 125 patients with primary aldosteronism from 97 patients with essential hypertension. Results of this novel assay significantly correlated with the results of radioimmunoassay (aldosterone, active renin concentration and renin activity) and liquid chromatography-tandem mass spectrometry (aldosterone). The analytical sensitivity of this particularly novel active renin assay was 0.1 pg/ml, which was better than that of radioimmunoassay (2.0 pg/ml). Using Bland-Altman plots with the mass-spectrometry values, both bias and limits of agreement with 95% confidence interval of the automated aldosterone assay were smaller than those of the radioimmunoassay, indicating smaller systemic errors in the novel measurement. The ratio of aldosterone-over-renin concentrations of 11.2 (ng/dl per pg/ml) provided 80.8% sensitivity and 94.9% specificity as a cut-off for differentiating primary aldosteronism from essential hypertension. This novel measurement is expected to be a clinically reliable alternative for conventional radioimmunoassay and to provide better throughput and cost-effectiveness in diagnosis of hyperaldosteronism from larger numbers of hypertensive patients in clinical settings.