Characterization of C5 Acylcarnitines and Related Dicarboxylic Acylcarnitines in Saudi Newborns: Screening, Confirmation, and Cutoff Variation.

Newborn screening (NBS) is a nationwide program for the early detection of disability in the Saudi population. This study focused on specific disorders related to organic acids that share C5 acylcarnitines derivatives and related dicarboxylic acylcarnitines as primary screening metabolites. We aimed to determine the frequency of C5 acylcarnitine derivatives and related dicarboxylic acylcarnitines among screened newborns; confirm truly positive screening results using urine organic acid analysis; and compare the cutoff values for C5, C5DC, and C5OH acylcarnitines from the selected analytical centers. Data from laboratory positively screened and confirmed samples from the Public Health Authority (PHA) over 3 years were retrieved and analyzed to determine the frequency of the selected metabolites and percentage of true positive results among the positively screened samples. We identified significant correlations among variables such as disease, sex, and C5 metabolites across different cities. We clarified the frequency of true positive results for C5 acylcarnitine derivatives and related dicarboxylic acylcarnitines among Saudi newborns and highlighted significant variations in cutoff values across analytical centers. These findings contribute to the enhancement of NBS protocols and early intervention strategies.