Abstract:

Objective To investigate the changes of 17 alpha-hydroxyprogesterone（17α-OHP） levels in preterm birth and low birth weight newborns in Weihai，and to establish a cut-off value for screening congenital adrenal hyperplasia（CAH）. Methods Totally，78 147 dry blood samples of neonatal genetic metabolic diseases from the Screening Center of Weihai Maternal and Child Health Care Hospital from January 2019 to December 2023 were collected. According to gestational age and birth weight，the newborns were classified into preterm birth group（4 596 cases），non-preterm birth group（73 551 cases），low birth weight group（2 775 cases） and non-low birth weight group（75 372 cases），respectively. The level of 17α-OHP was determined，and the positive rate of initial screening，positive rate of screening and positive predictive value of each group were compared. The cut-off value of 17α-OHP screening for CAH was established using the percentile method，with the 99.5th percentile（P_99.5） value as the upper limit of the cut-off value. Results Totally，745（0.953%） cases were positive at initial screening，229（0.293%） cases were positive at screening，and 3 cases of CAH were confirmed. The positive rates of initial screening and screening in preterm birth newborns and low birth weight newborns were higher than those in non-preterm birth newborns and non-low birth weight newborns，respectively（P<0.001）. Based on the P_99.5 value，the cut-off value was set at 38.0 nmol·L^-1 for preterm birth and/or low birth weight newborns and 10.5 nmol·L^-1 for other newborns. Compared with the current cut-off value，the number of recall reviews was decreased by 50.20%，and the positive predictive value was increased by 102.25%. No cases had been missed. Conclusions Preterm birth and low birth weight have effects on neonatal 17α-OHP levels. Each region should establish its own 17α-OHP cut-off value for neonatal CAH screening.

Key words: 17 Alpha-hydroxyprogesterone, Congenital adrenal hyperplasia, Neonatal genetic metabolic disease, Cut-off value