Age in days-related variations in neonatal blood carnitine concentrations and its clinical significance

Abstract

Objective To investigate the relationship between neonatal blood carnitine levels and the factors of gender, days after birth gestational age (GA) and birth weight (BW), and to provide some data for routine neonatal metabolic screening. Methods A total of 490 neonates from Department of Neonatology, the Sixth Affiliated Hospital of Sun Yat-Sen University and Women and Children′s Hospital of Sanshui District, Foshan during the period July 2012 to December 2015 were recruited in this study.They were divided into 3 groups according to days after birth, within 1 day after birth for group A (207 cases), 2-3 days for group B (153 cases), 4 to 14 days for group C (130 cases). Then heel peripheral blood were collected.Free carnitine(FC), total acylcarnitines (AC) and total carnitine (TC)concentrations were measured by using tandem mass spectrometry (MS-MS) and then tested for the association between the biomarkers and the factors of gender, days after birth, GA and BW. Results Concentrations of TC and AC tapered off from day 1 to day 14.Concentrations of TC, FC and AC were significantly higher in male-preterm-low birth weight infants compared with female-fullterm infants with normal birth weight infants in group A. The differences were statistically significant(all P 0.05). Conclusions Neonatal blood carnitine concentrations have negative relationship with age, GA and BW.Therefore, during routine neonatal metabolic screening, full consideration should be given to the factors which may have an important influence on the carnitine levels. Key words: Total carnitine; Free carnitine; Acylcarnitine; Infant, newborn