Tandem mass spectrometry in newborn screening

Abstract

Tandem mass spectrometry (MS/MS) has been used for sev-eral years to identify and measure carnitine esters in blood and urine of children suspected of having inborn errors of metab-olism. Indeed, acylcarnitine analysis is a better diagnostic test for disorders of fatty acid oxidation than organic acid analysis because it can often detect these conditions when the patient is not acutely ill.1 More recently, MS/MS has been used in pilot programs to screen newborns for these conditions and for dis-orders of amino and organic acid metabolism as well. The pur-pose of this article is to describe MS/MS and discuss its poten-tial role in newborn screening programs.