Evaluation of the immunoradiometric and electrochemiluminescence method for the measurement of serum insulin in children

Human insulin is a polypeptide hormone produced, stored, and secreted by the ß-cells in the pancreatic islets of Langerhans. Its secretion is stimulated by an increase of the glucose concentration in circulation. Non-radioactive assays are frequently used in many laboratories to measure hormone concentrations, as an alternative to the traditional “gold standard” radioimmuno- and immunoradiometric assays. The precise and reliable determination of the insulin concentration is an important concern in numerous diagnostic procedures. The aim of this study was to compare two commercially available assays (manual and automated) for measurement of serum insulin concentrations. Aliquots of the 86 randomly selected serum samples were measured by Elecsys Insulin Assay (cobas e411 immunoassay analyzer, Roche Diagnostics GmbH, Mannheim, Germany) and DIAsource INS-IRMA Kit (DIAsource ImmunoAssays S.A., Louvain-la-Neuve, Belgium). Compared assays exhibit good correlation (r = 0.996). Insulin concentrations were on average 4.2 μIU/mL lower (p < 0.05) with the cobas e411 immunoassay analyzer when compared to those measured with DIAsouce Immunoassay. Our findings suggest that electrochemiluminescence method on the cobas e411 analyzer and manual IRMA method offered by the DIAsource for the serum insulin determination could be considered interchangeable.