High efficiency of the aldosterone-to-renin ratio in precisely detecting primary aldosteronism

The aldosterone-to-renin ratio (ARR) is extensively used for primary aldosteronism detection. Chemiluminescence immune assay (CLIA) is newly applied in aldosterone and renin detection for calculating the aldosterone-to-renin ratio. The performance of new ARR in aldosteronism detection is poorly evaluated. We aim to estimate the diagnostic value of this new aldosterone-to-renin ratio by highly standardized and clinically based protocol. Four hundred and forty-two patients were enrolled in our retrospective study. They went to the first affiliated hospital of Sun Yat-sen University with difficult-to-control hypertension. Primary aldosteronism diagnosis was based on clinical criteria, including a saline infusion test and other necessary inspections. ARR was calculated from plasma aldosterone and renin measured by CLIA. The cutoff value was determined and the diagnostic value was evaluated. The cutoff value of ARR for primary aldosteronism diagnosis was 28.3, with a sensitivity of 87.6%, specificity of 100%, negative-predictive value of 96.4%, and positive-predictive value of 100%. Then, we found that Age was weakly correlated with ARR. The cutoff values of ARR for primary aldosteronism diagnosis in 26-45-, 46-65-, and 66-85-year-old patients were, respectively, 29.45, 27.95, and 28.4, with sensitivities of 87.5%, 87.7%, and 87.5%, specificities of 100% for all, negative-predictive values of 97.7%, 94.3%, and 96.3%, and positive-predictive values of 100% for all. ARR generated by CLIA is a good diagnostic test for primary aldosteronism without making a false-positive diagnosis. Although ARR is correlated with age, ARR cutoff values for different ages are not more efficient than that for total sample in primary aldosteronism diagnosis.