Diagnostic performance of the ARCHITECT C-Peptide immunoassay.
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.
Schultess
Jan
J
Abbott GmbH and Co. KG, Wiesbaden, Germany. jan.schultess@abbott.com
van Duren
Cathelijne
C
Martens
Mike
M
Costa
Marta
M
Llop
Teresa
T
Martí
Teresa
T
Eppinger
Martina
M
Hausmann
Michael
M
Krack
Wolfgang
W
Dhein
Jens
J
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
D002096:C-Peptide; D011933:Reagent Kits, Diagnostic