The Mouse C-peptide ELISA Kit is used to quantitatively measure the concentrations of C-peptide in mouse serum and plasma. This assay employs the quantitative sandwich enzyme immunoassay technique, in which C-peptide in the samples or standards are sandwiched between pre-coated C-peptide antibody and HRP-conjugated antibody specific for C-peptide. Following a wash to remove any unbound reagent, the TMB substrate solution is added to the wells and color develops in proportion to the amount of C-peptide bound in the initial step. The color development is stopped and the intensity of the color is measured at 450 nm via a microplate reader. This kit has been validated with various criteria, including sensitivity, specificity, precision (less than 15%), linearity, and recovery. The product instructions are access to more information.

C-peptide is a 31-amino-acid-peptide released from the pancreatic beta cells during cleavage of insulin from proinsulin. It does not actually affect the blood sugar. C-peptide is produced in equimolar amounts to endogenous insulin, so it is useful as a marker of insulin production. Moreover, C-peptide degrades more slowly in the body than insulin does. It is therefore a useful and widely used method of assessing pancreatic beta-cell function. The C-peptide test is used to help evaluate blood sugar disorders, including type 1 or type 2 diabetes. A normal C-peptide range is 0.5 to 2.0 nanograms per milliliter. Most C-peptide is metabolized by the kidneys with 5-10% then excreted unaltered in the urine, which makes it inaccurate in the measurement of C-peptide in individuals with chronic kidney disease.