Exploration of cut-off values of amino acid levels in premature infants in Sichuan / 中华实用儿科临床杂志

ABSTRACT

Objective:To detective the cut-off values of amino acid levels in premature infants in Sichuan.Methods:Data of newborns screening for inherited metabolic diseases (IMD) by tandem mass spectrometry in Sichuan Province from January 2018 to December 2019 were retrospectively analyzed.They were divided into premature infant group ( n=2 264, 1 312 males and 952 females) and full-term infant group ( n=53 275, 28 269 males and 25 006 females). The cut-off values of amino acids in dry blood spots were expressed as percentage ( P0.5 - P99.5), and rank sum test was used for comparison between preterm and full-term infants. Results:(1) The distribution of 11 amino acids [alanine (ALA), arginine (ARG), citrulline (CIT), glycine(GLY), leucine (LEU), methionine (MET), ornithine (ORN), phenylalanine (PHE), proline (PRO), tyrosine (TYR) and valine (VAL)] in premature infants were abnormal.(2) The cut-off values of amino acids in premature infants were as follows: ALA: 135.20-552.33 μmol/L, ARG: 1.34-47.04 μmol/L, CIT: 5.66-32.02 μmol/L, GLY: 181.48-909.93 μmol/L, LEU : 71.10-283.29 μmol/L, MET: 4.21-34.51 μmol/L, ORN: 40.58-293.76 μmol/L, PHE: 23.60-106.30 μmol/L, PRO: 77.76-358.24 μmol/L, TYR: 27.52-352.91 μmol/L, VAL: 53.74-228.37 μmol/L.(3) The cut-off values of amino acid in full-term infants were as follows: ALA: 135.20-552.33 μmol/L, ARG: 1.30-42.73 μmol/L, CIT: 5.92-30.35 μmol/L, GLY: 208.17-980.09 μmol/L, LEU: 72.91-287.49 μmol/L, MET: 4.27-33.90 μmol/L, ORN: 48.40-305.59 μmol/L, PHE: 27.63-92.27 μmol/L, PRO: 97.38-372.75 μmol/L, TYR: 40.19-276.54 μmol/L, VAL: 65.75-237.92 μmol/L.(4) Except for PHE ( Z=-0.58, P>0.05), the other indicators were significantly different between 2 groups [ALA ( Z=-15.32, P<0.05), ARG ( Z=-5.62, P<0.05), CIT ( Z=-5.86, P<0.05), GLY ( Z=-14.52, P<0.05), LEU ( Z=-5.62, P<0.05), MET ( Z=-5.22, P<0.05), ORN ( Z=-13.01, P<0.05), PRO ( Z=-22.09, P<0.05), TRY ( Z=-2.09, P<0.05), VAL ( Z=-17.82, P<0.05)]. Conclusions:The establishment of the cut-off values of amino acids in premature infants in Sichuan provides a theoretical basis for laboratory diagnosis of IMD screening, which enhances the accuracy of diagnosis and avoids excessive medical treatment.