• Clinical validation of cutoff target ranges in newborn screening of metabolic disorders by tandem mass spectrometry: a worldwide collaborative project.

      McHugh, David M S; Cameron, Cynthia A; Abdenur, Jose E; Abdulrahman, Mahera; Adair, Ona; Al Nuaimi, Shahira Ahmed; Åhlman, Henrik; Allen, Jennifer J; Antonozzi, Italo; Archer, Shaina; et al. (Nature Publishing Group, 2011-03)
      PURPOSE: To achieve clinical validation of cutoff values for newborn screening by tandem mass spectrometry through a worldwide collaborative effort. METHODS: Cumulative percentiles of amino acids and acylcarnitines in dried blood spots of approximately 25–30 million normal newborns and 10,742 deidentified true positive cases are compared to assign clinical significance, which is achieved when the median of a disorder range is, and usually markedly outside, either the 99th or the 1st percentile of the normal population. The cutoff target ranges of analytes and ratios are then defined as the interval between selected percentiles of the two populations. When overlaps occur, adjustments are made to maximize sensitivity and specificity taking all available factors into consideration. RESULTS: As of December 1, 2010, 130 sites in 45 countries have uploaded a total of 25,114 percentile data points, 565,232 analyte results of true positive cases with 64 conditions, and 5,341 cutoff values. The average rate of submission of true positive cases between December 1, 2008, and December 1, 2010, was 5.1 cases/day. This cumulative evidence generated 91 high and 23 low cutoff target ranges. The overall proportion of cutoff values within the respective target range was 42% (2,269/5,341). CONCLUSION: An unprecedented level of cooperation and collaboration has allowed the objective definition of cutoff target ranges for 114 markers to be applied to newborn screening of rare metabolic disorders.
    • Enhanced interpretation of newborn screening results without analyte cutoff values.

      Marquardt, Gregg; Currier, Robert; McHugh, David M S; Gavrilov, Dimitar; Magera, Mark J; Matern, Dietrich; Oglesbee, Devin; Raymond, Kimiyo; Rinaldo, Piero; Smith, Emily H; et al. (Nature Publishing Group, 2012-07)
      To improve quality of newborn screening by tandem mass spectrometry with a novel approach made possible by the collaboration of 154 laboratories in 49 countries. A database of 767,464 results from 12,721 cases affected with 60 conditions was used to build multivariate pattern recognition software that generates tools integrating multiple clinically significant results into a single score. This score is determined by the overlap between normal and disease ranges, penetration within the disease range, differences between conditions, and weighted correction factors. Ninety tools target either a single condition or the differential diagnosis between multiple conditions. Scores are expressed as the percentile rank among all cases with the same condition and are compared to interpretation guidelines. Retrospective evaluation of past cases suggests that these tools could have avoided at least half of 279 false-positive outcomes caused by carrier status for fatty-acid oxidation disorders and could have prevented 88% of known false-negative events. Application of this computational approach to raw data is independent from single analyte cutoff values. In Minnesota, the tools have been a major contributing factor to the sustained achievement of a false-positive rate below 0.1% and a positive predictive value above 60%.
    • Neonatal Screening in Europe Revisited: An ISNS Perspective on the Current State and Developments Since 2010.

      Loeber, J Gerard; Platis, Dimitris; Zetterström, Rolf H; Almashanu, Shlomo; Boemer, François; Bonham, James R; Borde, Patricia; Brincat, Ian; Cheillan, David; Dekkers, Eugenie; et al. (MDPI, 2021-03-05)
      Neonatal screening (NBS) was initiated in Europe during the 1960s with the screening for phenylketonuria. The panel of screened disorders ("conditions") then gradually expanded, with a boost in the late 1990s with the introduction of tandem mass spectrometry (MS/MS), making it possible to screen for 40-50 conditions using a single blood spot. The most recent additions to screening programmes (screening for cystic fibrosis, severe combined immunodeficiency and spinal muscular atrophy) were assisted by or realised through the introduction of molecular technologies. For this survey, we collected data from 51 European countries. We report the developments between 2010 and 2020 and highlight the achievements reached with the progress made in this period. We also identify areas where further progress can be made, mainly by exchanging knowledge and learning from experiences in neighbouring countries. Between 2010 and 2020, most NBS programmes in geographical Europe matured considerably, both in terms of methodology (modernised) and with regard to the panel of conditions screened (expanded). These developments indicate that more collaboration in Europe through European organisations is gaining momentum. We can only accomplish the timely detection of newborn infants potentially suffering from one of the many rare diseases and take appropriate action by working together. Keywords: ISNS; International Society for Neonatal Screening; congenital endocrine disorders; congenital metabolic disorders; dried blood spot screening; neonatal screening; newborn screening; public health; rare diseases.