On the stability of immunoreactive glucagon in plasma samples

The stability of glucagon immunoreactivity in plasma samples, as measured with antiserum 30K, has been investigated. Post-prandial blood samples were collected and processed both with added Trasylol at 4 degrees C and without Trasylol at room temperature. Incubation at room temperature for up to 7h without added Trasylol did not result in significant loss of 30K-immunoreactive glucagon. Blood samples both from non-diabetic and diabetic persons could be collected and centrifuged at room temperature and stored at -20 degrees C without Trasylol for more than 2 months without loss of 30K-immunoreactivity, as compared to Trasylol-containing controls kept at 4 degrees C during handling. The distribution of 30K-immunoreactive glucagon over the various components, obtained after chromatography of plasma on Ultrogel AcA54, was not significantly altered when blood samples, both from normal persons and from patients with chronic renal failure, were processed at room temperature and subsequently stored at -20 degrees C without addition of Trasylol. Our results indicate that collection and centrifugation of blood at room temperature without the addition of a proteinase inhibitor and subsequent storage at -20 degrees C does not result in loss of 30K-immunoreactive glucagon.