title: Comparison of HPLC and small column (CDTect) methods for disialotransferrin.
abstract: BACKGROUND
  Current methods for determination of carbohydrate-deficient transferrin (CDT) are based on separation of the CDT fraction by ion-exchange chromatography on minicolumns and quantification by immunoassay. Alternatively, the transferrin isoforms can be separated by HPLC anion-exchange chromatography and quantified by absorbance. This method has been reported to improve the validity of CDT as a marker of chronic alcohol abuse.
  
  
  METHODS
  HPLC on either MonoQ or ResourceQ anion-exchange columns was used to separate and quantify isoforms of transferrin with detection at 460 nm. The result was expressed as the percentage of the disialo form (pI 5.7) of total transferrin (DST). The commercial CDTect assay was used as a comparison method. Serum samples from nondrinkers (n = 57), moderate drinkers (n = 77), and heavy drinkers (n = 139) were analyzed.
  
  
  RESULTS
  In ROC analysis for differentiation between moderate and heavy drinkers, the area under the curve (AUC) for the HPLC method was 0.87 (95% confidence interval, 0.81-0.93), whereas that for CDTect was 0.72 (95% confidence interval, 0.64-0.80). At 90% specificity, the sensitivity of DST was 63% (95% confidence interval, 53-73%) compared with 33% (22-44%) for CDT. The reference interval of the HPLC method was 0.68-1.7%.
  
  
  CONCLUSIONS
  The HPLC anion-exchange method for quantification of CDT provides substantially better separation between moderate and heavy drinkers than the CDTect method.
authors.affiliation: Department of Clinical Chemistry, Helsinki University Central Hospital, 00290 Helsinki, Finland. ursula.turpeinen@hus.fi
authors.forename: U
authors.initials: U
authors.lastname: Turpeinen
authors.forename: T
authors.initials: T
authors.lastname: Methuen
authors.forename: H
authors.initials: H
authors.lastname: Alfthan
authors.forename: K
authors.initials: K
authors.lastname: Laitinen
authors.forename: M
authors.initials: M
authors.lastname: Salaspuro
authors.forename: U H
authors.initials: UH
authors.lastname: Stenman
mesh_terms: D000437:Alcoholism / Q000175:diagnosis* / Q000191:economics; D015415:Biomarkers / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000191:economics / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000191:economics; D003362:Cost-Benefit Analysis; D006801:Humans; D008297:Male; D019158:N-Acetylneuraminic Acid / Q000737:chemistry*; D020033:Protein Isoforms / Q000097:blood; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results; D014168:Transferrin / Q000031:analogs & derivatives / Q000032:analysis* / Q000737:chemistry
chemical_list: D015415:Biomarkers; D020033:Protein Isoforms; D014168:Transferrin; C056759:carbohydrate-deficient transferrin; D019158:N-Acetylneuraminic Acid