title: Matrix-assisted laser desorption/ionization for simultaneous quantitation of (acyl-)carnitines and organic acids in dried blood spots.
abstract: BACKGROUND
  Screening for inborn errors of metabolism using mass spectrometry is part of nationwide newborn screening programs and involves the detection of disease relevant (acyl-)carnitines and organic acids from dried blood spots. Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a well-established tool for proteomics approaches. In recent years, this technique has become more and more integrated in analysis and identification of small metabolites and disease biomarkers in daily clinical laboratories.
  
  
  METHODS
  We used a combination of both MALDI and high-resolution accurate mass (HR/AM) mass spectrometry using a linear ion trap-Orbitrap for the identification of small molecules from dried blood spots that serve as biomarkers for inborn errors of metabolism. The levels of detected metabolite species were compared between healthy newborns and affected patients with various inborn errors of metabolism using isotopically labeled internal standards and new bioinformatics software, respectively.
  
  
  RESULTS
  (Acyl-)carnitine levels from normal and affected patients could be quantified and differentiated. Additionally, using the high resolving power of full scan Orbitrap mass spectrometry and novel software tools we demonstrated the identification and quantification of disease-specific organic acids.
  
  
  CONCLUSIONS
  MALDI-HR/AM and full scan spectra to obtain information for the metabolic status of patients is a promising complementary approach to electrospray ionization mass spectrometry by simplified sample preparation, facilitating the screening of hundreds of metabolites from small sample volumes.
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Ostermann
authors.forename: Rebecca
authors.initials: R
authors.lastname: Dieplinger
authors.forename: Nikola M
authors.initials: NM
authors.lastname: Lutsch
authors.forename: Kerstin
authors.initials: K
authors.lastname: Strupat
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Metz
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Mechtler
authors.forename: David C
authors.initials: DC
authors.lastname: Kasper
mesh_terms: D002331:Carnitine / Q000031:analogs & derivatives* / Q000097:blood; D059788:Dried Blood Spot Testing / Q000379:methods*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008661:Metabolism, Inborn Errors / Q000175:diagnosis*; D015997:Neonatal Screening; D009930:Organic Chemicals / Q000097:blood*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D009930:Organic Chemicals; C116917:acylcarnitine; D002331:Carnitine