Characterization and comparison of immune-depleted and hereditary factor-VII-deficient plasmas as substrate plasmas for factor VII assays.
The functional activity of coagulation factors usually is determined using bioassays dependent on substrate plasmas deficient in the factor being measured. These are obtained most often from patients with hereditary deficiency and are frequently poorly characterized. The authors characterized seven commercially available hereditary Factor-VII-deficient substrate plasmas in terms of Factor VII activity and antigen level, and then compared them with a Factor-VII-deficient plasma prepared by immunoadsorption. All of the hereditary Factor-VII-deficient plasmas contained significant quantities of Factor VII antigen (120-217 ng/mL; normal, 250-600 ng/mL). One of the commercial substrate plasmas showed significant factor VII coagulant activity with a human thromboplastin. The sensitivity of the Factor VII assay system was dependent on both the source of Factor-VII-deficient plasma and the origin of the thromboplastins; human thromboplastin was more sensitive than rabbit thromboplastin, and immune-depleted plasma gave the most sensitive assay with each thromboplastin. These results indicate that immunoadsorbed plasma may be a superior reagent for coagulation factor assays.
D001780:Blood Coagulation Tests; D005165:Factor V / Q000032:analysis; D005167:Factor VII / Q000032:analysis*; D005168:Factor VII Deficiency / Q000097:blood*; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D007163:Immunosorbent Techniques; D011247:Pregnancy; D011863:Radioimmunoassay; D013925:Thromboplastin
D005165:Factor V; D005167:Factor VII; D005340:Fibrinogen; D013925:Thromboplastin