Newborn Screening for Inborn Metabolic Disorders in Iranian Infants: Comprehensive Evaluation of the Paya Hamsan Derivatized Technique for Tandem Mass Spectrometry

Abstract

Background: Screening newborns for inborn metabolic disorders (IMDs) is important for early diagnosis and prevention of serious health complications. Tandem mass spectrometry (MS/MS) analysis of metabolites in dried blood spots (DBSs) has improved the accuracy and scope of neonatal screening. This study evaluated the performance of the Paya Hamsan Newborn Screening Derivatized (PH-NBS-D) MS/MS method for detecting and quantifying amino acids and acylcarnitines in newborns.

Methods: The PH-NBS-D MS/MS assay was validated using DBS samples analyzed on an AB SCIEX 3200 MS/MS system. Its performance was compared with two commercially available newborn screening kits, MassChrom® and ClinSpot®, using clinical DBS specimens. Analytical performance was assessed according to relevant Clinical and Laboratory Standards Institute (CLSI) guidelines, including accuracy, precision, and linearity.

Results: The PH-NBS-D assay showed good analytical performance, with recovery rates ranging from 91% to 115%. Repeatability CVs ranged from 4.1% to 12.9%, between-day variation from 0.0% to 8.6%, and total precision CVs from 7.1% to 25.7%. Linearity was excellent across the evaluated concentration ranges, with R² values above 0.99. The PHNBS-D assay showed comparable performance to the two commercial kits. In clinical samples, percentage deviations remained within the predefined acceptance limits (±30%), and Bland–Altman analysis showed no significant systematic bias, indicating good agreement between the methods.

Conclusions: The PH-NBS-D MS/MS assay showed satisfactory analytical performance and good agreement with the evaluated commercial newborn screening assays. These findings support its potential use for measuring amino acids and acylcarnitines in DBS specimens and for further evaluation in routine newborn screening.