Screening for non-classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) is performed with baseline 17-hydroxyprogesterone (17OHPb) and confirmed with the ACTH test. Because the cutoff level of 17OHPb that prompts an ACTH testing is still a matter of discussion, we evaluated the levels of 17OHPb in diagnosing CAH caused by 21OHD. An ACTH (0.25 mg IV) test was performed in 87 hyperandrogenic women, 24.8±0.8 years old. 17OHP levels greater than 1,500 ng/dL, 60min after administration of ACTH were considered diagnostic. 21OHD was confirmed in 11 patients (12.6%); in the remainder 76 the test was negative. Sensitivity, specificity, positive and negative predictive values for 17OHPb >200 ng/dL were 0.91, 0.62, 0.26 and 0.98, respectively. For 17OHPb >350 ng/dL these values were 0.91, 0.91, 0.59 and 0.99 and for 17OHPb >500 ng/dL, 0.82, 0.99, 0.9 and 0.97. Clinical findings (hirsutism, menstrual irregularities and obesity) and levels of androstenedione and total testosterone were similar between both groups. We conclude that clinical findings and androgen levels cannot differentiate patients with and without 21OHD, and suggest the ACTH test to be performed whenever 17OHPb is >350 ng/dL, a highly sensitive cutoff with good negative predictive value.
Hyperandrogenism; Non-classic congenital adrenal hyperplasia; 21-Hydroxylase; 17-Hydroxyprogesterone; ACTH test; Hirsutism
