title: Unknown peaks in GC-MS analyses of Guthrie cards blood samples might be the result of sample contamination by the black markings of the card.
abstract: Azelaic acid, sometimes found during analysis of Guthrie card blood samples, may be derived from the printing ink used to mark the spotting area.
authors.affiliation: Department of Pediatrics, Otto-von-Guericke University, Magdeburg, Germany. thomas.brune@medizin.uni-magdeburg.de
authors.forename: T G
authors.initials: TG
authors.lastname: Brune
authors.forename: A Ch
authors.initials: ACh
authors.lastname: Lambrecht
authors.forename: H G
authors.initials: HG
authors.lastname: Koch
mesh_terms: D003998:Dicarboxylic Acids / Q000652:urine*; D005189:False Positive Reactions; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007231:Infant, Newborn; D008661:Metabolism, Inborn Errors / Q000652:urine*; D015997:Neonatal Screening; D011933:Reagent Kits, Diagnostic
chemical_list: D003998:Dicarboxylic Acids; D011933:Reagent Kits, Diagnostic; C010038:azelaic acid