Essential, non-essential and conditionally essential amino acid blood concentrations play a critical role in newborns. We aimed to quantitate most of these amino acids in the blood of full-term breastfed infants, perinatally and correlate the obtained values with their birth weight. Breastfed full-term infants (n = 12,000; 6000 males, 6000 females) with birth weight 2000-4000 g were divided into 4 equal groups: Group A, 2000-2500 g; B, 2500-3000 g; C, 3000-3500 g and D, 3500-4000 g. Blood samples as Dried Blood Spots (DBS) were collected on the 3rd day of life and analyzed via liquid chromatography-tandem mass spectrometry (LC-MS/MS) protocol. Blood concentrations of the amino acids, Phenylalanine, Leucine, Glutamine, Ornithine, Alanine, Tyrosine and Glycine in full-term breastfed newborns, were found to be related to their birth weight, perinatally. On the contrary, no relationship between birth weight and blood concentrations of the amino acids Valine, Methionine, Citrulline and Arginine was found. Due to the number of the samples, data from this study could be applied as neonatal screening reference values for full-term breastfed newborns in relation to their birth weight.
Keywords: Newborn screening; conditionally essential amino acids; essential amino acids; non-essential amino acids; reference values.