The measurement to bloodspot amino acids and acyl carnitines using tandem mass spectrometry in identification of infantile jaundice

Abstract

Objective To identify infantile jaundice by measurement of bloodspot amino acids and acyl carnitines using tandem mass spectrometry(MS/MS), through which we explore the method to distinguish the biliary atresia (BA) from intrahepatic cholestasis (IC). Methods All subjects were aged from 1 to 5 months, including 13 cases of BA and 12 cases of IC, as well as 13 patients with idiopathic neonatal hepatitis. 31 patients without any hepatic diseases were set as control. The concentrations of 11 kinds of amino acids, free carnitine (C0)and 30 kinds of acylcarnitines were measured using MS/MS. Results The concentration of C0 was 66 ± 20μmol/L in BA group, which was much higher than IC group (50 ± 19 μmol/L) and control (30 ± 10μmol/L). The curve area under the ROC of C0 for diagnosis of BA was higher than ratio of direct-bilirubin to total-bilirubin, total bilirubin, alkaline phosphatase, and total cholic acid respectively. The concentrations of methionine, phenylalanine, tyrosine, citrulline, ornithine, and glycine, as well as alanine in BA and IC were significantly higher than control. The concentrations of leucine (88 ± 27 μmol/L), valine (90 ± 31 μmol/L) and the ratio of leucine with valine to tyrosine was 2.70 ± 0.82 in IC group, which was respectively lower than BA group (115 ± 28μmol/L, 116 ± 27μmol/L, 3.51 ± 0.83) and control (106 ± 31 μmol/L, 103 ± 26μmol/L, 4.29 ± 0.94) significantly (P＜0.01 ). Conclusions Bloodspot concentrations measure and comparison of amino acids, free carnitine and acylcarnitines changes in BA and IC are useful to distinguish infantile jaundice. Key words: Tandem mass spectrometry; Amino acids; Carnitine; Biliary atresia; Cholestasis