Evaluation of an ELISA assay for total proinsulin and establishment of reference values during an oral glucose tolerance test in a healthy population

Abstract

Objectives Assessment of the analytical performance of the Total Proinsulin ELISA Kit (Millipore) and determination of reference values. Design and methods Imprecision, specificity, antibodies interference and reference values in normoglycaemic non-obese adults were determined. Results The inter-assay CV is < 6.9%, the limits of detection and quantification are 0.2 and 0.6 pmol/L. Molar cross-reactivity of split proinsulins varies from 103 to 92.5%. The interference of anti-(pro)insulin antibodies can be eliminated with the use of polyethylene glycol. The reference values are 2.7–14.2 pmol/L at fasting, 8.5–56.5 pmol/L at T30 min and 11.9–70.5 pmol/L at T120 min during an OGTT. Conclusion The reference values established for this kit, which showed good analytical performances, allow for a better assessment of pathologies associated with increased proinsulinaemia.