C4A and short chain acyl-CoA dehydrogenase deficiency: The C4/C2 and C4/C3 ratios were also above the cutoff values in individuals with confirmed SCADD or IBDD, and compared with the no-gene-mutation group, the mean C4/C2 or C4/C3 ratios of the confirmed cases obtained from the initial NBS by MS/MS were nearly double the cutoffs.