Summary
A new solid phase enzyme-linked immunosorbent assay (ELISA) was developed for the quantitation of human Factor VII antigen (F VII Ag), using a monospecific rabbit anti-F VII antiserum. Anti-F VII F(ab′)2 fragments were adsorbed to polystyrene plates. The binding of serial dilutions of control or test plasma, containing F VII, was detected by incubation with peroxidase-labeled anti- FV II IgG followed by the addition of hydrogen peroxyde and O-phenylenediamine. This ELISA is specific, sensitive (detection limit: 0.05%) and accurate (coefficient of variation: 1.5-4% for within- and 1.6-9% for between-assays). F VII coagulant activity (F VII C) and F VII Ag were determined in large populations of controls and patients. In normal plasma (n = 38), F VII Ag ranged from 83 to 117% and the correlation coefficient between F VII Ag and F VII C was 0.94. In patients with severe (F VII C inf. 1%) congenital F VII deficiency (n = 5), F VII Ag was undetectable in two cases (inf. 0.05%) and markedly reduced (0.35 to 5.6%) in the three other cases. In patients with liver cirrhosis (n = 15), F VII Ag ranged from 21 to 59% and was in good correlation with F VII C (r = 0.84). In dicoumarol treated patients (n = 15), the levels of F VII Ag ranged from 51% to 79% and a poor correlation (r = 0.52) with F VIIC was observed. In “compensated” DIC (n = 5), levels of F VII Ag varied from 60 to 186%, with significantly higher F VII C levels (from 143 to 189%). In contrast, in “decompensated” DIC (n = 7), low F VII Ag and F VII C levels were observed (from 7 to 27%). In patients with deep-vein thrombosis (n = 25), high levels of F VII Ag (from 102 to 136%) and F VII C (from 110 to 150%) were demonstrated. In surgical patients, no significant difference was observed before and one day after intervention.
Key words
Factor VII - Congenital deficiency - Acquired deficiency - ELISA
