Age-related variations in acylcarnitine and free carnitine concentrations measured by tandem mass spectrometry.

Background: The acylcarnitine profiles obtained from dried blood spots on "Guthrie cards" have been widely used for the diagnosis and follow-up of children suspected of carrying an inherited error of metabolism, but little attention has been paid to potential age-related variations in the reference values. In this study, we evaluated the variations in free carnitine and acylcarnitine concentrations with age, as measured by tandem mass spectrometry.

Methods: Filter-paper blood spots were collected from 433 healthy individuals over a period of 17 months.