Performance of LC/MS/MS in Analyzing Multiple Amino Acids and Acylcarnitines in Dried Blood Spot of Very Low Birth Weight, Low Birth Weight, and Normal Weight Neonates

Background: Amino acid (AA) and acylcarnitine (AC) are important biomarkers of protein and fatty acid metabolism. Examining their levels in newborns may reveal multiple inherited metabolic diseases. However, they have rarely been assessed in very low birth weight (VLBW) neonates, low birth weight (LBW) neonates and rarely been compared with normal weight (NW) neonates. The aim of the study was to identify the AA and AC profiles in dried blood spot (DBS) specimens of LBW and VLBW neonates, then compare with NW neonates, and make a contribution to the determination of cutoff values of VLBW and LBW neonates. Methods: Liquid Chromatography tandem mass spectrometry (LC/MS/MS) is an excellent tool for quantitatively detecting AA and AC profiles. This article verified the precision, accuracy, and linearity of the LC/MS/MS method in AA and AC detection, then analyzed AA and AC profiles in DBS of VLBW, LBW and NW neonates, and compared the difference of AA and AC in the three groups. Results: The results showed that the LC/MS/MS method had wide linear range, satisfied precision and reproducibility in detecting AA and AC in DBS specimens; most AA and AC concentrations significantly correlated with birth weight in DBS samples (p < 0.05). Conclusions: The results suggested that VLBW and LBW neonates have different metabolic or nutritional status with NW neonates and different AA and AC cutoffs should be defined for them to reduce the risk of false-positive cases.