OBJECTIVE: Newborn screening (NBS) on dried blood spots (DBS) is mandatory under Italian law (No. 167/2016), despite a fair heterogeneity in the panel of diseases being monitored. Classical Congenital Adrenal Hyperplasia (CAH) has been recently included in the NBS program of the Abruzzo region, providing screening tests to over 16,000 newborns to date. According to our workflow, 445 (2.73%) second-tier tests (2-TT) were performed, 7 (0.04%) newborns required further attention, and 4 (0.02%) positive cases were found. Our NBS lab has already set customized cutoffs based on gestational weeks; however, other factors, such as different types of nutrition, could influence 17-α-hydroxyprogesterone levels (17-OH).

MATERIALS AND METHODS: We retrospectively evaluated the CAH screening performed on DBS specimens collected within the first 120 hours (colostrum production time) after birth. We compared 17-OHP and associated markers levels between newborns who consumed formula milk and those who received colostrum. The analysis focused on 17-OHP levels in 6,384 infants, of which 439 were formula-fed while 5,945 breast-fed.

RESULTS: 17-OHP levels showed statistically significant differences (p<0.0001) depending on the different types of nutrition, as well as some markers quantified by the second-tier test (2-TT). Then, we set customized cut-off values for 17-OHP according to the types of nutrition. As a preliminary approach, we analyzed steroids in two infant formulas and three colostrum samples, observing the absence of cortisol in formula milk.

CONCLUSIONS: These results lay the foundation to remodulate the current cutoffs in order to reduce 2-TTs, thus optimizing our analytical performance.