Poor Performance of Angiotensin II Enzyme-Linked Immuno-Sorbent Assays in Mostly Hypertensive Cohort Routinely Screened for Primary Aldosteronism

Abstract

Primary aldosteronism (PA) is the most common, but broadly underdiagnosed, form of hormonal hypertension. To improve screening procedures, current biochemical approaches aim to determine newly appreciated angiotensin II (Ang II) and calculate the aldosterone-to-angiotensin II ratio (AA2R). Thus, the aim of this study was to assess the diagnostic performance of these screening tests in comparison to the aldosterone-to-direct renin ratio (ADRR), which is routinely used. Cheap and available ELISA was used for Ang II measurement. To our knowledge, this is the first study of this laboratory method’s usage in PA. The study cohort included 20 PA patients and 80 controls. Ang II concentrations were comparable between PA and non-PA patients (773.5 vs. 873.2 pg/mL, p = 0.23, respectively). The AA2R was statistically significantly higher in PA group when compared with non-PA (0.024 vs. 0.012 ng/dL/pg/mL, p p < 0.01). The sensitivity and specificity of the AA2R were 70% and 76.2%, respectively. Thus, the AA2R was not effective as a screening tool for PA. Our data provide important arguments in the discussion on the unsatisfactory accuracy of renin–angiotensin system evaluation by recently repeatedly used ELISA tests.

Keywords

• hormonal hypertension
• primary aldosteronism
• angiotensin II
• aldosterone-to-angiotensin 2 ratio
• aldosterone-to-direct renin ratio
• enzyme-linked immunosorbent assay