title: Preanalytical and analytical variation of surface-enhanced laser desorption-ionization time-of-flight mass spectrometry of human serum.
abstract: BACKGROUND
  Surface-enhanced laser desorption-ionization time-of-flight (SELDI-TOF) mass spectrometry of human serum is a potential diagnostic tool in human diseases. In the present study, the preanalytical and analytical variation of SELDI-TOF mass spectrometry of serum was assessed in healthy individuals.
  
  
  METHODS
  Serum and plasma were obtained from healthy human individuals. Protein peaks in human serum and plasma were determined by SELDI-TOF mass spectrometry.
  
  
  RESULTS
  The protein peaks in serum in healthy individuals showed no variation with gender, age, fasting, or diurnal rhythm. The intensity of protein peaks changed significantly during clotting of serum from 30 to 60 min, followed by smaller changes from 60 to 120 min. The intensity of protein peaks changed after 60-min storage of serum at room temperature, whereas no changes were observed for storage on ice. The number of reproducible protein peaks in serum was determined on WCX2, SAX2, and IMAC30 arrays as 29, 34, and 36, respectively. The average coefficient of variation (CV) of the mass value of protein peaks was 0.03%. The intra-assay CV of peak intensity on IMAC30 arrays was 16% (10%-36%, n=8) for 36 peaks, inter-assay CV was 18% (6%-34%, n=4) for 16 peaks, and inter-individual CV was 38% (16%-56%, n=16) for 20 peaks.
  
  
  CONCLUSIONS
  The pre-analytical and analytical conditions of SELDI-TOF mass spectrometry of serum have a significant impact on the protein peaks, with the number of peaks low and the assay variation high. Consequently, SELDI-TOF mass spectrometry of serum needs further evaluation before application in clinical diagnostics.
authors.affiliation: Department of Clinical Biochemistry, Glostrup Hospital, Glostrup, Denmark. ja@dcb-glostrup.dk
authors.forename: Jakob
authors.initials: J
authors.lastname: Albrethsen
authors.forename: Rikke
authors.initials: R
authors.lastname: Bøgebo
authors.forename: Jesper
authors.initials: J
authors.lastname: Olsen
authors.forename: Hans
authors.initials: H
authors.lastname: Raskov
authors.forename: Steen
authors.initials: S
authors.lastname: Gammeltoft
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001798:Blood Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013499:Surface Properties
chemical_list: D001798:Blood Proteins