biostudies-literatureAtkins AEIowa Ladies Football Academy447-451https://www.ebi.ac.uk/biostudies/studies/S-EPMC6754489biostudies-literatureUnknown10(4)The Iowa Newborn Screening (NBS) Program began screening for very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) in 2003. Untreated VLCAD can lead to liver failure, heart failure, and death. Current confirmatory testing recommendations by the American College of Medical Genetics (ACMG) for VLCAD list molecular and functional analysis (i.e., fibroblast fatty acid oxidation probe) as optional. This can lead to misclassification of VLCAD carriers as false positives. Iowa implemented a comprehensive VLCAD confirmatory testing algorithm at the beginning of 2016 that included both molecular and fibroblast analysis. Here, we compare the historic multi-algorithmic confirmatory testing protocol (2005-2016) to this comprehensive protocol (2016-2017). A metabolic specialist reviewed all medicalJournal of community geneticsMisclassification of VLCAD carriers due to variable confirmatory testing after a positive NBS result.PMC6754489n/aPhillips EKTarini BACalhoun ARULAtkins AEfalseMisclassification of VLCAD carriers due to variable confirmatory testing after a positive NBS result.The Iowa Newborn Screening (NBS) Program began screening for very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) in 2003. Untreated VLCAD can lead to liver failure, heart failure, and death. Current confirmatory testing recommendations by the American College of Medical Genetics (ACMG) for VLCAD list molecular and functional analysis (i.e., fibroblast fatty acid oxidation probe) as optional. This can lead to misclassification of VLCAD carriers as false positives. Iowa implemented a comprehensive VLCAD confirmatory testing algorithm at the beginning of 2016 that included both molecular and fibroblast analysis. Here, we compare the historic multi-algorithmic confirmatory testing protocol (2005-2016) to this comprehensive protocol (2016-2017). A metabolic specialist reviewed all medical2019-01-01T00:00:00Z2019 Oct2025-04-04T22:11:41.667Z2019-10-16T07:03:28ZS-EPMC67544893072139110.1007/s12687-019-00409-8