Pancreatic beta-cell function is usually assessed by the measurement of plasma insulin concentration in various clinical situations. However, the advent of an assay for the measurement of connecting-peptide (C-peptide) concentration in plasma has provided a further method for the assessment of the secretory capacity of the pancreatic beta cell in clinical disorders, particularly in the investigation of hypoglycaemia. The metabolism and immunoassay methodology of C-peptide are reviewed, and its application in clinical practice is outlined.
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