Serial ARR Testing Guides Primary Aldosteronism Work-Up

Serial aldosterone-to-renin ratio (ARR) measurements provided complementary diagnostic information in a retrospective study published in The Journal of Clinical Endocrinology & Metabolism , with the interpretation rule changing the balance between sensitivity and specificity in evaluating primary aldosteronism (PA). The investigators compared four approaches to interpreting the first two ARR results.

Investigators analyzed 342 patients referred for suspected PA who had two valid ARR measurements and a final clinical diagnosis; 214 (62.6%) were classified as having PA and 128 (37.4%) as having essential hypertension. The measurements were obtained on separate days under unchanged standardized testing conditions.

The four approaches were the first ARR alone, the arithmetic mean of the first two measurements, at least one positive result, and two positive results. At an ARR threshold of 49 ng/L per mIU/L, requiring two positive measurements yielded 82.2% sensitivity and 71.9% specificity, with the highest balanced accuracy among the strategies at that threshold, 77.1%. Treating either measurement as positive increased sensitivity to 93.9% but reduced specificity to 37.5%.

At the same threshold, PA prevalence was 21.3% among patients with two negative results and 83.0% among those with two positive results. The two discordant patterns had PA prevalences of 36.8% and 36.0%, placing both between the concordant groups.

Averaging the measurements produced an area under the receiver operating characteristic curve of 0.827, compared with 0.809 for the first result alone against the final clinical diagnosis; the difference was not statistically significant (p=0.102). The authors concluded that serial results should be interpreted according to the diagnostic objective, while noting that the retrospective, single-center design, selected referral population, diagnostic incorporation and verification biases, and assay-method change limit generalizability.

Source: Parasiliti-Caprino M, Bollati M, Barba L, et al. Interpreting serial aldosterone-to-renin ratio measurements in the diagnostic work-up of primary aldosteronism. J Clin Endocrinol Metab. 2026. doi:10.1210/clinem/dgag381