# Plasma aldosterone response to ACTH stimulation test for diagnosis of primary aldosteronism: a cross-sectional study

## TL;DR

This study shows that measuring plasma aldosterone 20 minutes after an ACTH test can help diagnose primary aldosteronism without needing more complex tests.

## Contribution

The study introduces a simplified diagnostic method for primary aldosteronism using a single ACTH stimulation test.

## Key findings

- PAC at 20 minutes after ACTH stimulation was significantly associated with PA diagnosis.
- The proposed cut-off of 52 ng/dL achieved 71.4% sensitivity and 96.6% specificity for PA diagnosis.
- The method may be useful when standard confirmation tests for PA are not feasible.

## Abstract

The diagnosis of primary aldosteronism (PA) requires screening and confirmation testing. The present study examined whether the 1 µg ACTH stimulation test for plasma aldosterone concentration (PAC) can accurately diagnose PA by bypassing the regular confirmatory steps of PA diagnosis.

A cross-sectional study with a total of 36 patients with an aldosterone-renin ratio (ARR) > 20 ng/dL per ng/m/hr were included. The confirmation test for PA was performed by saline infusion and the patients were categorized into PA and non-PA. PAC was collected at 20 and 40 min after 1 µg ACTH stimulation test. Multivariable logistic regression analysis was performed, and the associations are presented as odds ratios (OR) and 95% confidence intervals (CI). Diagnostic accuracy is presented as AuROC.

Multivariable analysis found only PAC at 20 min after ACTH stimulation showed significant association with a diagnosis of PA (OR 1.18, 95%CI (0.99, 1.31), p = 0.040). AuROC for this value was 0.95 and the proposed cut-off was 52 ng/dL with a sensitivity of 71.4% and a specificity of 96.6%.

Diagnosing PA may be aided by PAC at 20 min following 1 µg ACTH stimulation. This value may be used with patients for whom the confirmation test for PA cannot be conducted.

The online version contains supplementary material available at 10.1186/s12902-024-01563-y.