Application of tandem mass spectrometry for blood acylcarnitine and amino acid profiling in differentiating etiologies of neonatal cholestasis.

Objective: This study aims to evaluate the clinical value of combined blood acylcarnitine (BA) and amino acid profiling in differentiating the etiologies of neonatal cholestasis (NC) and to provide a novel approach for the early and accurate identification of biliary atresia and non-biliary atresia forms of NC. Methods: Clinical data were retrospectively collected from 180 newborns with NC who were admitted to this hospital between January 2023 and January 2026. The patients were divided into a biliary atresia group and a non-biliary atresia group based on whether they ultimately developed BA. Baseline characteristics and laboratory test results were obtained for all participants. Plasma acylcarnitine levels were detected by tandem mass spectrometry, and serum amino acid concentrations were determined using high-performance liquid chromatography/tandem mass spectrometry. Acylcarnitine and amino acid concentrations were then compared between the two groups. The diagnostic ability of individual metabolites was assessed by calculating the area under the curve (AUC). A composite detection model was established by performing binary classification analysis, and its predictive accuracy was evaluated. Results: Compared with the non-biliary atresia group, patients in the biliary atresia group showed significantly higher levels of direct bilirubin/total bilirubin ratio, Conclusion: Overall, the combined evaluation of plasma acylcarnitine and amino acid profiles provides a more accurate approach for identifying the causes of neonatal cholestasis, such as biliary atresia, through multiple factors. This method provides necessary non-invasive reference for diagnosing neonatal cholestasis and should be widely promoted for clinical use.