title: Use of a common standard for comparison of insulin C-peptide measurements by different laboratories.
abstract: A synthetic human C-peptide analogue has been used as a common standard for the comparison of insulin C-peptide measurements in seven assay systems in six laboratories. Even in terms of this common standard there was statistically significant numerical heterogeneity between laboratories for estimates of the C-peptide content of the same plasma samples. However, the consistency in ranking order of estimates of C-peptide in the plasma samples between laboratories suggests that laboratories are in most cases measuring at least similar immunoreactive constituents and that a reference plasma might prove useful in comparing results between laboratories. Until a more suitable reference material is available, the synthetic analogue, 64 formyllysine C-peptide, in ampoules coded 76/561, will be made available for research purposes.
mesh_terms: D007516:Adenoma, Islet Cell / Q000097:blood; D002096:C-Peptide / Q000031:analogs & derivatives / Q000097:blood*; D003920:Diabetes Mellitus / Q000097:blood; D006801:Humans; D010190:Pancreatic Neoplasms / Q000097:blood; D010455:Peptides / Q000097:blood*; D011384:Proinsulin / Q000097:blood; D011786:Quality Control; D011863:Radioimmunoassay / Q000379:methods
chemical_list: D002096:C-Peptide; D010455:Peptides; D011384:Proinsulin