| With the widespread use of expanded newborn screening by tandem mass spectrometry, there is a corresponding increase in the need for confirmatory acylcarnitine analysis. Typically performed on derivatized serum samples, the test allows for the quantitation of a large number of acylcarnitine species, and aids in the diagnosis of various inborn errors of metabolism. However, it is important to understand potential problems and pitfalls inherent in acylcarnitine analysis, including time and temperature-dependent hydrolysis of acylcarnitines during derivatization, lack of commercial availability of pure standard materials, ion suppression caused by co-elution/co-migration of analytes, pre-analytical stability of certain analytes, and the effects of diet on measured acylcarnitine levels. Appropriate clinical cases will be discussed as they pertain to these scenarios. |
