Abstract
Since measurement of serum C-peptide (CPR) is important in assessing insulin secretion, several serum CPR assay kits have become commercially available for measurement.To evaluate the correlation between kits, we undertook linearity and cross-reactivity experiments using the highly sensitive IRMA kit (Eiken)(kit E), C-peptide kit III (TFB)(kit T), and C-peptide RIA Shionogi II (Shionogi)(kit S). In normal CPR concentration, linearity and recovery showed permeable results and an appropriate correlation between kits. In low CPR concentration, however, no linearity was seen in CPR kits using polyclonal antibody and they tended to show higher titer than the kit using monoclonal antibody, making it necessary to consider kit accuracy when measuring low CPR concentration.
