title: Six methods for the determination of C-peptide evaluated.
abstract: Six assays for C-peptide were evaluated. Five assays were radioimmunoassays; one was a chemiluminescence assay. The within-run coefficient of variation ranged between 2.1 and 22.9%. The methods correlated well with each other (r = 0.925 to 0.978). There were, however, proportional biases between the assays, in particular in the higher concentration range. All assays were linear up to at least 4.5 ng/ml C-peptide concentration. All assays were easy to perform. However, the systematic bias between the assays demonstrates that further effort is needed to standardize the measurement of C-peptide. In the mean-time, we recommend that laboratories conducting C-peptide measurements establish local, method-specific reference ranges.
authors.affiliation: Department of Internal Medicine, University Hospital Freiburg, Germany. MSNauck@med1.ukl.uni-freiburg.de
authors.forename: M S
authors.initials: MS
authors.lastname: Nauck
authors.forename: M A
authors.initials: MA
authors.lastname: Nauck
authors.forename: M A
authors.initials: MA
authors.lastname: Nauck
authors.forename: W
authors.initials: W
authors.lastname: März
authors.forename: H
authors.initials: H
authors.lastname: Wieland
mesh_terms: D002096:C-Peptide / Q000097:blood*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008163:Luminescent Measurements; D008297:Male; D011863:Radioimmunoassay
chemical_list: D002096:C-Peptide