Screening for 21-hydroxylase–deficient nonclassic adrenal hyperplasia among hyperandrogenic women: a prospective study

In the 1999 study, researchers assessed the use of basal 17-hydroxyprogesterone (17-HP) levels to screen for 21-hydroxylase-deficient nonclassic adrenal hyperplasia (NCAH) in hyperandrogenic women. The study included 8 healthy controls, 20 NCAH patients, and 284 hyperandrogenic women. They found that a 17-HP level of <2 ng/mL had a 100% specificity in the follicular phase, but specificity decreased in the luteal phase. Sensitivity was high for 17-HP levels >2 ng/mL in NCAH patients, especially in the morning. The positive predictive value (PPV) varied with the cutoff level, with higher cutoffs yielding higher PPVs. The study concluded that a basal 17-HP level is a useful screening tool for NCAH, recommending a cutoff level of 3 ng/mL for maximum PPV with adequate sensitivity, noting that a cutoff of 2 ng/mL is best for maximizing detection, despite a lower PPV.