Measurement of fibrinogen adsorption from blood plasma using 125I-fibrinogen and a direct ELISA technique

A direct enzyme-linked immunosorbent assay (ELISA), using a polyclonal anti-fibrinogen conjugated to horseradish peroxidase, was used to detect fibrinogen adsorption from blood plasma to ten different materials. Adsorption was also measured with [125I]-fibrinogen. The materials studied included glass, Biomer, Immulon I, and a series of hydroxyethylmethacrylate (HEMA) and ethylmethacrylate (EMA) co-polymers. For all the materials studied, the results from the ELISA technique closely paralleled those obtained using [125I]-fibrinogen. The cross-reactivity of the antibody with proteins other than fibrinogen was generally small. Both experimental methods detected the presence of a maximum in fibrinogen adsorption (as a function of the plasma dilution) to the more hydrophobic materials. For all but two HEMA/EMA co-polymers, a linear correlation between the ELISA and [125I]-fibronogen measurements was indicated by inspection of cross plots as well as by a statistical test.