Endocrine Abstracts

Introduction: Measurement of the baseline level of 17-hydroxyprogesterone (17OHP) is a screening test for NCAH, a less severe form of congenital adrenal hyperplasia.

Aim: A real-life verification of the currently adopted 17OHP threshold (≥2.0 ng/ml) at which the further diagnostic (cosyntropin stimulation test) should be performed.

Material and methods: The study included 400 patients (385 females and 15 males) referred to the Department of Endocrinology in 2004-2021 due to clinical suspicion of NCAH. In each subject a standard 250 µg cosyntropin stimulation test was performed. NCAH diagnosis was made if cosyntropin-stimulated 17OHP level exceeded 10.0 ng/mL. The ROC curve for baseline 17OHP levels was determined, and the baseline cut-off point with the highest sensitivity and specificity was established. The study was approved by the Ethics Board of JUMC.

Results: 85 patients (83 females and two males; 21.3% of study group) were diagnosed with NCAH. The 17OHP cut-off value that qualified patients best for further diagnostics was 2.36 ng/ml (sensitivity and specificity 88.2% and 87.0%, respectively). Sensitivity and specificity for the guideline recommended 17OHP cut-off level (≥2.0 ng/ml) were 90.6% and 77.5%, respectively. In women with menstrual disorders the best 17OHP level cut-off point was 2.38 ng/ml (sensitivity and specificity: 88.1% and 85.5%, respectively), while for those without menstrual irregularities it was 2.79 ng/ml (sensitivity and specificity: 95.3%: 83.7%, respectively).

Conclusions: Our results suggest considering an upward shift in the 17OHP threshold at which patients suspected for NCAH should be referred for further evaluation. This may reduce the number of unnecessary cosyntropin stimulation tests, particularly in patients which may not require any treatment. Stratification of 17OHP cut-off values according the clinical presentation of patients suspected for NCAH may also be considered.