Effect of hemolysis on insulin determination by the Beckman Coulter Unicell DXI 800 immunoassay analyzer

Objectives: To evaluate the effect of hemolysis on the measurement of insulin using the Beckman Coulter Unicell DXI 800 immunoassay analyzer. Design and methods: Insulin concentrations were measured using the Beckman Coulter Unicell DXI 800. Interference studies were conducted by mixing plasma of known insulin concentrations with hemolysates of increasing hemoglobin concentration. Hemolysates were prepared by osmotic shock. A change of >10% from baseline results was taken as evidence of significant interference. Results: Hemolysates mediated a concentration-dependent reduction in insulin concentration. Conclusions: A concentration-dependent negative bias in the measurement of insulin is associated with increasing degrees of hemolysis on the Beckman Coulter Unicell DXI 800. (C) 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.