title: Measurement of factor VIII procoagulant antigen in normal subjects and in hemophilia A patients by an immunoradiometric assay and by an enzyme-linked immunosorbent assay.
abstract: Factor VIII coagulant antigen (FVIII:Ag) and FVIII coagulant activity (FVIII:C) were measured in 102 healthy individuals, in 5 hemophilia A carriers and in 21 hemophilia A patients before and after infusion of heat-treated high-purity FVIII concentrates. Factor VIII:Ag was determined by a solid-phase micro enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies and by a conventional solid-phase immunoradiometric assay (IRMA). Factor VIII:C was assessed using a one-stage assay. The micro ELISA was decidedly more precise than the IRMA. There was a close correlation between the results obtained by the three assays in the plasma of healthy subjects and in hemophilia A carriers. After transfusion of FVIII concentrates to hemophilia A patients, the FVIII:Ag recoveries were significantly lower than the FVIII:C recoveries and the biological half-life of FVIII:Ag was significantly shorter than for FVIII:C. The calculated half-life of FVIII:C was longer than in any previous study.
mesh_terms: D000293:Adolescent; D000328:Adult; D000941:Antigens / Q000032:analysis; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005167:Factor VII / Q000032:analysis / Q000276:immunology; D005169:Factor VIII / Q000032:analysis* / Q000378:metabolism / Q000627:therapeutic use; D005260:Female; D006467:Hemophilia A / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D011874:Radiometry
chemical_list: D000941:Antigens; C031500:factor VII related antigen; D005167:Factor VII; D005169:Factor VIII