Not So Rare: Errors of Metabolism During the Neonatal Period

Sandra A. Banta-Wright, MN, RNC, NNP; Robert D. Steiner, MD


NAINR. 2003;3(4) 

In This Article

Tandem Mass Spectrometry

With increasing use of tandem mass spectrometry (MS/MS), the analysis of acylcarnitines and amino acids in dried filter paper blood spot (Guthrie) specimens has proven useful as a method for mass newborn screening for a number of amino acid, fatty acid oxidation, organic acid, and urea cycle disorders.[7] This technique has been referred to as expanded newborn screening. The analysis usually requires only one or two dried filter paper blood spots. In addition, it is automated and usually takes only 1 to 2 minutes per sample. When a newborn is suspected of having an EM, the regional academic or state laboratory should be notified to facilitate a more rapid screening result. However, the result is dependent on the sample being in the laboratory and acceptable quality of the blood spot. The ability to use MS/MS to provide direction toward the differential diagnosis and the collection of confirmatory laboratory tests for many metabolic disorders has been life saving for many newborns. However, not every state or region has MS/MS available for expanded newborn screening. In addition, the test is not 100% sensitive for some disorders. The result may be available in some cases only after the neonate has already presented clinically and is in the neonatal intensive care unit in critical condition.


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