Assay of factor VII antigen by enzyme-linked immunosorbent assay (ELISA)

This paper introduces a newly developed enzyme-linked immunosorbent assay (ELISA) method, using monospecific anti-human factor VII rabbit IgG, to quantify antigen levels of factor VII. The procedure is relatively simple, its method is remarkably specific and reproducible. Its sensitivity to detect factor VII antigen is as low as 0.015 U/ml, when factor VII antigen in 1 ml normal plasma is arbitrarily defined as 1 unit. The level of factor VII antigen in 4 patients with congenital factor VII deficiency and their family members was investigated through this ELISA and the results correlated well with those obtained by electroimmunoassay previously described. The significant correlation between the antigen levels and activity of factor VII was demonstrated in 4 patients with congenital factor VII deficiency and their family members, normal individuals and patients with liver disease. However, the level of factor VII antigen in patients treated with warfarin was higher than their coagulation activity.