title: Diagnostic performance of the ARCHITECT C-Peptide immunoassay.
abstract: BACKGROUND
  Measurement of C-peptide under standardized conditions provides a sensitive and well-established assessment of beta-cell function. We describe the analytical and clinical validation of an automated, microparticle-based chemiluminescent immunoassay method. The assay is designed to measure C-peptide in human serum, plasma and urine.
  
  
  METHODS
  Assay performance characteristics such as precision and recovery were measured according to protocols established by the Clinical Laboratory Standards Institute (CLSI). A reference range study was conducted. Analytical sensitivity and specificity, interfering substances, recovery, and linearity studies were performed. Method comparison, against the ADVIA Centaur C-Peptide assay (Siemens), was evaluated with clinical specimens from patients with abnormal insulin secretion.
  
  
  RESULTS
  The detection limit for this assay was 0.01 ng/mL. Functional sensitivity (inter-assay imprecision < or = 20%) was 0.015 ng/mL at a coefficient of variation (%CV) of 11.2%. Total imprecision was below 6.5% CV. The assay was linear upon dilution. Comparison with the ADVIA Centaur C-Peptide assay yielded a correlation coefficient (r) of 0.99.
  
  
  CONCLUSIONS
  The ARCHITECT C-Peptide assay measures C-peptide rapidly, accurately, and precisely in human serum, plasma and urine. It provides useful improvements for beta-cell function testing and for evaluating the clinical status of a patient in combination with other diabetes markers.
authors.affiliation: Abbott GmbH and Co. KG, Wiesbaden, Germany. jan.schultess@abbott.com
authors.forename: Jan
authors.initials: J
authors.lastname: Schultess
authors.forename: Cathelijne
authors.initials: C
authors.lastname: van Duren
authors.forename: Mike
authors.initials: M
authors.lastname: Martens
authors.forename: Marta
authors.initials: M
authors.lastname: Costa
authors.forename: Teresa
authors.initials: T
authors.lastname: Llop
authors.forename: Teresa
authors.initials: T
authors.lastname: Martí
authors.forename: Martina
authors.initials: M
authors.lastname: Eppinger
authors.forename: Michael
authors.initials: M
authors.lastname: Hausmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Krack
authors.forename: Jens
authors.initials: J
authors.lastname: Dhein
mesh_terms: D002096:C-Peptide / Q000032:analysis* / Q000097:blood / Q000652:urine; D003920:Diabetes Mellitus / Q000175:diagnosis; D044882:Glucose Metabolism Disorders / Q000175:diagnosis*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008163:Luminescent Measurements; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
chemical_list: D002096:C-Peptide; D011933:Reagent Kits, Diagnostic