Screening threshold for congenital adrenal hyperplasia in preterm and full-term infants by an indirect method / 中华实用儿科临床杂志

ABSTRACT

Objective:To analyze the difference and reliability of blood 17-hydroxyprogesterone (17-OHP), an indirect screening index for congenital adrenal hyperplasia (CAH), between preterm and full-term infants.Methods:In this retrospective cross-sectional study, a total of 210 285 newborns who underwent CAH screening at the Neonatal Screening Center of Shanghai Children′s Hospital from January 2019 to December 2022 were collected, including 14 312 premature infants and 195 973 full-term infants.The concentration of 17-OHP in dried blood spots on filter paper was determined by an automatic fluorescence analyzer.The distribution of 17-OHP levels in preterm and full-term infants and its statistical index were analyzed.The Kolmogorov-Smirnov test was used for normal distribution.The skewed distribution data was converted into approximately normal distribution using Box-Cox.Outliers were eliminated by the interquartile range method.The cumulative frequency distribution map was drawn by R language programming.The 99.5 th percentile value was used as the screening threshold and compared with the reference value given by the manufacturer or laboratory and with the reference change value (RCV). Results:According to the threshold provided by the laboratory, 26.76‰ of premature infants were tested positive in preliminary screening, and 4 were confirmed with an incidence of 1∶3 578, while 0.79‰ of full-term infants were tested positive in preliminary screening, and 11 were confirmed with an incidence of 1∶17 816.The thresholds for CAH screening established indirectly were 20.35 nmol/L in preterm infants and 10.78 nmol/L in full-term infants.The relative deviations between the indirect CAH screening thresholds and the manufacturer′s or laboratory′s CAH screening thresholds were higher than the RCV, respectively.According to the indirect CAH screening thresholds, the negative and positive coincidence rates of 65 samples in 13 batches from the Centers for Disease Control and Prevention interlaboratory quality assessment program in the United States reached 100%.A retrospective analysis of 210 285 neonates showed that 17-OHP concentration was higher than the screening threshold in all CAH-positive neonates.The application of this screening threshold reduced the false positive rate of preterm infants by 59.79%.Conclusions:It is feasible to establish the CAH screening thresholds for premature and full-term infants by an indirect method, which can improve the efficiency of screening and provide better diagnostic basis for clinical practice.