Steroid profiling for congenital adrenal hyperplasia by tandem mass spectrometry as a second-tier test reduces follow-up burdens in a tertiary care hospital: a retrospective and prospective evaluation.

BACKGROUND: Newborn screening for congenital adrenal hyperplasia (CAH) based on measuring 17-hydroxyprogesterone (17-OHP) by immunoassay generates a number of false-positive results, especially in preterm neonates. We applied steroid profiling by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a second-tier test in newborns with positive CAH screening and evaluated its clinical utility in a tertiary care hospital setting.

METHODS: By performing a 4-year retrospective data review, we were able to test 121 dried blood spots from newborns with positive CAH screening for 17-OHP, androstenedione and cortisol levels by LC-MS/MS. We prospectively evaluated the clinical utility of steroid profiling after the implementation of steroid profiling as a second-tier test in our routine clinical practice. During the 2-year prospective study period, 104 cases with positive initial screening by FIA were tested by LC-MS/MS. Clinical and laboratory follow-up were performed for at least 6 months.

RESULTS: The preterm neonates accounted for 50.7% (76/150) and 70.4% (88/125) of screening-positive cases in retrospective and prospective cohorts, respectively. By applying steroid profiling as a second-tier test for positive CAH screening, we eliminated all false-positive results and decreased the median follow-up time from 75 to 8 days.

CONCLUSIONS: Our data showed that steroid profiling reduced the burden of follow-up exams by improving the positive predictive value of the CAH screening program. The use of steroid profiling as a second-tier test for positive CAH screening will improve clinical practice particularly in a tertiary care hospital setting where positive CAH screening from preterm neonates is frequently encountered.