title: Postanalytical tools improve performance of newborn screening by tandem mass spectrometry.
abstract: OBJECTIVE
  The purpose of this study was to compare performance metrics of postanalytical interpretive tools of the Region 4 Stork collaborative project to the actual outcome based on cutoff values for amino acids and acylcarnitines selected by the California newborn screening program.
  
  
  METHODS
  This study was a retrospective review of the outcome of 176,186 subjects born in California between 1 January and 30 June 2012. Raw data were uploaded to the Region 4 Stork Web portal as .csv files to calculate tool scores for 48 conditions simultaneously using a previously unpublished functionality, the tool runner. Scores for individual target conditions were deemed informative when equal or greater to the value representing the first percentile rank of known true-positive cases (17,099 cases in total).
  
  
  RESULTS
  In the study period, the actual false-positive rate and positive predictive value were 0.26 and 10%, respectively. Utilization of the Region 4 Stork tools, simple interpretation rules, and second-tier tests could have achieved a false-positive rate as low as 0.02% and a positive predictive value >50% by replacing the cutoff system with Region 4 Stork tools as the primary method for postanalytical interpretation.
  
  
  CONCLUSIONS
  Region 4 Stork interpretive tools, second-tier tests, and other evidence-based interpretation rules could have reduced false-positive cases by up to 90% in California.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Hall
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Gregg
authors.initials: G
authors.lastname: Marquardt
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: David M S
authors.initials: DM
authors.lastname: McHugh
authors.affiliation: California Department of Public Heath, Richmond, California, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Currier
authors.affiliation: California Department of Public Heath, Richmond, California, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Tang
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Stoway
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Piero
authors.initials: P
authors.lastname: Rinaldo
mesh_terms: D000596:Amino Acids / Q000097:blood; D002140:California; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood; D019295:Computational Biology; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D020407:Internet; D008297:Male; D008910:Minnesota; D015997:Neonatal Screening / Q000379:methods*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012984:Software; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000596:Amino Acids; C116917:acylcarnitine; D002331:Carnitine