Figure 2.

Algorithm for the diagnostic evaluation of newborns with an elevated C₅ acylcarnitine concentration in an NBS blood spot. An asterisk (*) indicates that NBS was not available as a clinical test (research only). AC = acylcarnitine analysis; AG = acylglycine analysis; C₅AC = C₅ acylcarnitine; H = abnormally elevated; IVC = isovalerylcarnitine; IVG = isovalerylglycine; MBC = 2-methylbutyrylcarnitine; MBG = 2-methylbutyrylglycine; N = normal; ND = 932C→T mutation not detected; OA = organic acid analysis; PVA = pivalic acid (a component of several antibiotic medications [Abdenur et al. 1998]); SBCAD-D = short/branched-chain acyl-CoA dehydrogenase deficiency (2-methylbutyrylglycinuria).