Is a systematic adrenocorticotropic hormone (ACTH) stimulation test useful in diagnosing nonclassical congenital adrenal hyperplasia (NCAH)?

The ACTH stimulation test is the gold standard for diagnosing NCAH. However, this test has a human and material cost. While some teams perform it as a second-line test, others use it as a first-line test to avoid false negatives associated with single basal 17-hydroxyprogesterone (17-OHP) serum levels. In this prospective, single-center, cross-sectional observational study, we included 210 women aged from 15 to 41 who were referred for oligoanovulation and/or hyperandrogenism from November 2022 to June 2024. In this population, we determined the proportion of false negatives for NCAH using basal 17-OHP serum levels by performing ACTH stimulation tests. Among the 210 patients included, no NCAH was diagnosed, and no false negatives of basal 17-OHP serum levels were identified. Basal 17-OHP serum levels were significantly higher in PCOS patients but remained below the 2 ng/ml threshold and were significantly correlated with hormonal and ultrasound markers of PCOS. Consequently, the systematic use of the ACTH stimulation test in women with hyperandrogenism and/or oligoanovulation does not appear to be a cost-effective diagnostic strategy.