Establishing a new screening 17 hydroxyprogesterone cut-off value and evaluation of the reliability of the long intramuscular ACTH stimulation test in the diagnosis of nonclassical congenital adrenal hyperplasia.

OBJECTIVE Nonclassical congenital adrenal hyperplasia (NCAH) is a common genetic transmitted endocrinological disease. The validity of screening by using a 17 hydroxyprogesterone (17 OH-P) cut-off level of 2 ng/ml is controversial due to the frequent overlap with the polycystic ovary syndrome (PCOS). The availability of the standard intravenous cosyntropin (ACTH) formula is a problem in many countries including our country and the diagnostic test is performed by using the intramuscular depot form. In this study, we aimed to determine our own cut-off value for screening and to test the reliability of long intramuscular ACTH stimulation test in our patients. PATIENTS AND METHODS One hundred and seventy-five fertile age women whose basal follicular phase 17 OH-P level above 2 ng/ml were included in the study. All of the patients underwent an intramuscular long cosyntropin (ACTH) stimulation test. RESULTS 17 OH-P levels were above 10 ng/ml in 16 of 175 (9.14%) patients who were compatible with the diagnosis of NCAH. There was no significant difference between NCAH, PCOS and idiopathic hyperandrogenism (IH) groups in terms of hirsutism and hyperandrogenemia. In ROC analysis, 3.19 ng/ml was found to be a reliable cut-off value (AUC: 0.698, 95% GA: 0.540-0.855, p <0.05). In the extended intramuscular ACTH stimulation test, sensitivity increased from 56.2% to 91.6% at 180th minute CONCLUSIONS: Our study gives a perspective about the detection of screening threshold value for the diagnosis of NCAH and the availability of the intramuscular long ACTH stimulation test.