The quantitative method for determining acylcarnitine profile developed in the Masdiag Laboratory is an extension and complement to the method available in the newborn screening program. Separation of acylcarnitines on a chromatographic column enables accurate quantitative evaluation of concentrations, separation of isomers, and interfering substances (such as drugs). The test provides more clinically useful information, for example, it allows to differentiate propionic academia from methylmalonic academia.