title: Application of a C-peptide electrospray ionization-isotope dilution-liquid chromatography-tandem mass spectrometry measurement procedure for the evaluation of five C-peptide immunoassays for urine.
abstract: This study applied electrospray ionization-isotope dilution-liquid chromatography-tandem mass spectrometry for the evaluation of five urinary C-peptide immunoassays via split-sample measurements. The immunoassays measured in duplicate in the same run, the comparison method in triplicate over different runs. From the data, the within-run imprecision and the method comparison total RSDs were calculated. Regression analysis revealed on the one hand systematic differences, on the other, an excellent correlation between the test and comparison methods. From the spread of the data around the regression line in comparison with the 95% prediction intervals from the total RSD, sample-related effects and/or specificity problems were apparent and investigated.
authors.affiliation: Laboratorium voor Analytische Chemie, Faculteit Farmaceutische Wetenschappen, Universiteit Gent, Harelbekestraat 72, B-9000 Gent, Belgium.
authors.forename: Colette
authors.initials: C
authors.lastname: Fierens
authors.forename: Dietmar
authors.initials: D
authors.lastname: Stöckl
authors.forename: Dimitri
authors.initials: D
authors.lastname: Baetens
authors.forename: André P
authors.initials: AP
authors.lastname: De Leenheer
authors.forename: Linda M
authors.initials: LM
authors.lastname: Thienpont
mesh_terms: D002096:C-Peptide / Q000737:chemistry* / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007554:Isotopes; D011786:Quality Control; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D002096:C-Peptide; D007554:Isotopes