OBJECTIVETo investigate the feasibility of analyzing acylcarnitine in dry filter-paper blood spots by liquid chromatography-tandem mass spectrometry (LC-MS/MS) which could be applied to detect inborn errors of metabolism in neonates.

METHODSWe obtained filter-paper blood from 26 dead infants from a neonatal intensive care unit (NICU) between October 1, 2008 and September 30, 2009. Acylcarnitine and amino acid profiles were obtained with LC-MS/MS. Four infants underwent routine autopsy. The postmortem blood specimens were compared with newborn blood specimens, and with specimens obtained from older infants with metabolic disorders.

RESULTSOf all the 26 patients, 5 (19.2%) were diagnosed as having different kinds of diseases: 3 with methylmalonic acidemia (the concentration of C3, and the ratio of C3/C16, C3/C2 increased), 1 with maple syrup urine disease (the concentration of leucine and isoleucine increased), and 1 with isovaleric acidemia (the concentration of C5 increased).

CONCLUSIONSPostmortem metabolic test can explain infant deaths and provide estimates of deaths attributable to inborn errors of metabolism in NICU. LC-MS/MS is suitable for analysis of postmortem specimens and can be considered for routine application in NICU autopsy.

Amino Acid Metabolism, Inborn Errors ; blood ; diagnosis ; Autopsy ; Carnitine ; blood ; Chromatography, Liquid ; methods ; Female ; Humans ; Infant, Newborn ; Intensive Care Units, Neonatal ; Male ; Tandem Mass Spectrometry ; methods