Crefcoeur Loek L, de Sain-van der Velden Monique G M, Ferdinandusse Sacha, Langeveld Mirjam, Maase Rose, Vaz Frédéric M, Visser Gepke, Wanders Ronald J A, Wijburg Frits A, Verschoof-Puite Rendelien K, Schielen Peter C J I
Department of Metabolic Diseases, Wilhelmina Children's Hospital University Medical Center Utrecht Utrecht The Netherlands.
Laboratory Genetic Metabolic Diseases, Amsterdam UMC University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam Gastroenterology and Metabolism Amsterdam The Netherlands.
JIMD Rep. 2020 Sep 8;56(1):95-104. doi: 10.1002/jmd2.12162. eCollection 2020 Nov.
Free carnitine has been measured in the Dutch newborn screening (NBS) program since 2007 with a referral threshold of ≤5 μmol/L, regardless of gestational age or birthweight. However, several studies suggest that carnitine concentrations may depend on gestational age and birthweight. We evaluated differences in postnatal day-to-day carnitine concentrations in newborns based on gestational age (GA) and/or weight for GA (WfGA).
A retrospective study was performed using data from the Dutch NBS. Dried blood spot (DBS) carnitine concentrations, collected between the 3rd and 10th day of life, of nearly 2 million newborns were included. Individuals were grouped based on GA and WfGA. Median carnitine concentrations were calculated for each group. Mann-Whitney tests, and chi-square tests were applied to test for significant differences between groups.
Preterm, postterm, and small for GA (SGA) newborns have higher carnitine concentrations at the third day of life compared to term newborns. The median carnitine concentration of preterm newborns declines from day 3 onwards, and approximates that of term newborns at the sixth day of life, while median concentrations of postterm and SGA newborns remain elevated at least throughout the first 10 days of life. Carnitine concentrations ≤5 μmol/L were found less frequently in SGA newborns and newborns born between 32 and 37 weeks of gestation, compared to term newborns.
Median carnitine concentrations in NBS DBS vary with day of sampling, GA, and WfGA. It is important to take these variables into account when interpreting NBS results..
自2007年起，荷兰新生儿筛查（NBS）项目开始检测游离肉碱，转诊阈值为≤5 μmol/L，无论胎龄或出生体重如何。然而，多项研究表明，肉碱浓度可能取决于胎龄和出生体重。我们根据胎龄（GA）和/或基于胎龄的体重（WfGA）评估了新生儿出生后每日肉碱浓度的差异。
使用荷兰NBS的数据进行了一项回顾性研究。纳入了近200万新生儿出生后第3天至第10天采集的干血斑（DBS）肉碱浓度数据。根据GA和WfGA对个体进行分组。计算每组的肉碱浓度中位数。应用曼-惠特尼检验和卡方检验来检验组间的显著差异。
与足月儿相比，早产儿、过期产儿和小于胎龄儿（SGA）在出生后第3天的肉碱浓度更高。早产儿的肉碱浓度中位数从第3天开始下降，在出生后第6天接近足月儿，而过期产儿和SGA新生儿的中位数浓度至少在出生后的前10天内一直保持升高。与足月儿相比，SGA新生儿以及孕32至37周出生的新生儿中，肉碱浓度≤5 μmol/L的情况较少见。
NBS DBS中的肉碱浓度中位数随采样日、GA和WfGA而变化。在解释NBS结果时考虑这些变量很重要。
