title: Comparison of newborn screening protocols for congenital adrenal hyperplasia in preterm infants.
abstract: OBJECTIVE
  To compare 2 screening protocols performed concurrently in Minnesota: (1) liquid chromatography tandem mass spectrometry steroid profiling as a second-tier test on positive fluoroimmunoassay (FIA) results; and (2) low-birthweight 3-screen protocol (FIA tests at <48 hours, 2 weeks, 4 weeks) on all infants <1800 g, regardless of result.
  
  
  METHODS
  Population-based study of all <1800 g infants (n = 8739) born in Minnesota from 2004-2010 comparing newborn screening performance metrics of 2-tier (FIA + liquid chromatography tandem mass spectrometry) protocol (2004-2010) vs 1-tier (FIA) low-birthweight 3-screen protocol (2006-2010). False positive (FP) rates were calculated per infant's final confirmatory result. Protocol results used in different time periods (2004-2005 vs 2006-2010) were compared by 2-sample tests of proportions; results of both protocols for 2006-2010 were compared by McNemar test.
  
  
  RESULTS
  First-tier testing of final dried blood spot result (n = 6625) of the low-birthweight 3-screen protocol during 2006-2010 reduced the FP rate more than 5-fold (P < .0001) compared with 2-tier testing of a single dried blood spot (n = 2114) from 2004-2005. In comparing results (n = 6625) of both protocols from 2006-2010, first-tier testing of final dried blood spot accounted for 23% of FPs; second-tier testing of the first dried blood spot accounted for 77%, yielding significantly more FP results (McNemar test, P < .0001).
  
  
  CONCLUSIONS
  Timing of dried blood spot collection rather than assay used played a more important role in reducing FP results of congenital adrenal hyperplasia newborn screening in low birthweight infants.
authors.affiliation: Division of Pediatric Endocrinology, Division of Genetics and Metabolism, Department of Pediatrics, University of Minnesota Amplatz Children's Hospital, Minneapolis, MN. Electronic address: saraf010@umn.edu.
authors.forename: Kyriakie
authors.initials: K
authors.lastname: Sarafoglou
authors.affiliation: Minnesota Department of Health, St. Paul, MN.
authors.forename: Amy
authors.initials: A
authors.lastname: Gaviglio
authors.affiliation: Minnesota Department of Health, St. Paul, MN.
authors.forename: Amy
authors.initials: A
authors.lastname: Hietala
authors.affiliation: Minnesota Department of Health, St. Paul, MN.
authors.forename: Garen
authors.initials: G
authors.lastname: Frogner
authors.affiliation: Minnesota Department of Health, St. Paul, MN.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Banks
authors.affiliation: Minnesota Department of Health, St. Paul, MN.
authors.forename: Mark
authors.initials: M
authors.lastname: McCann
authors.affiliation: Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN.
authors.forename: William
authors.initials: W
authors.lastname: Thomas
mesh_terms: D000312:Adrenal Hyperplasia, Congenital / Q000097:blood / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D002853:Chromatography, Liquid; D002985:Clinical Protocols; D059788:Dried Blood Spot Testing / Q000379:methods*; D005189:False Positive Reactions; D015200:Fluoroimmunoassay; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000097:blood / Q000175:diagnosis*; D015997:Neonatal Screening / Q000379:methods*; D011237:Predictive Value of Tests; D013256:Steroids / Q000097:blood; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D015415:Biomarkers; D013256:Steroids