LAUSR

Abstract The main aim of this study was to show the usefulness of DBS samples in the assessment of a newborn's vitamin D body supply. Currently, maternal serum or umbilical cord blood-derived serum determinations are routinely performed for this purpose. The research used the LC-MS/MS technique. The quantitative analyses of four vitamin D metabolites were carried out in three matrices including maternal serum, umbilical cord blood-derived serum and neonatal DBS. Validation specifically dedicated to the DBS-based methods was also an important goal. The obtained results were compared and the flow of vitamin D metabolites between mother and child was assessed. The mean concentration of 25(OH)D in maternal serum was 32.1 ± 14 ng/ml, in umbilical cord blood-derived serum was 20.7 ± 8.4 ng/ml, and in neonatal DBS was 23.8 ± 9.3 ng/ml. The 25(OH)D concentration in umbilical cord blood-derived serum was 65% of the maternal serum concentration. In contrast, the differences between umbilical cord blood-derived serum and neonatal DBS were not statistically significant. DBS could be used interchangeably with cord blood-derived serum to determine vitamin D status in neonates. Since maternal serum and cord blood-derived serum are not routinely collected matrices, DBS samples could simplify the screening of vitamin D status.