Influence of Heparin-Plasma, EDTA-Plasma, and Serum on the Determination of Insulin with Three Different Radioimmunoassays

Abstract

Insulin was measured with three radioimmunoassay methods: with double antibody precipitation (DA), ethanol precipitation (EP), and solid phase linked antibody (SP), respectively, on samples of serum and plasma, with heparin or EDTA as anticoagulants. EP and SP methods gave almost identical results for all forms of samples. Higher values were found with the DA method on heparin plasma. This effect disappeared at low concentrations of heparin. It is concluded that the presence of heparin only affects radioimmunoassays for insulin involving DA precipitation.

Key Words:

• Anticoagulants
• double antibody radioimmunoassay
• heparin
• insulin radioimmunoassay
• plasma
• serum