title: A precision study of a photo-optical factor VIII assay technic.
abstract: Various methods of factor VIII analysis with a wide range of accuracies as confirmed by calculated coefficients of variation have been devised. The authors report a technic of factor VIII assay using a photo-optical clot-detection instrument with commercially available sources of factor VIII-deficient plasma and lyophilized normal control plasma, and compare its accuracy, ease of performance and reliability with those of existing methods. The accuracy of the technic was established by a survey of a normal control group, which revealed a mean value of 100% factor VIII activity, range 55-200%. The coefficients of variation of this unique technic, determined both by clotting time in sec (1.4%) and by the derived percentage activity (7.0%), reflect the greater reproducibility and reliability of the assay as compared with previously reported methods. We feel that this method of factor VIII assay should be utilized for specific diagnostic information regarding patients who have factor VIII disorders.
mesh_terms: D001780:Blood Coagulation Tests; D005169:Factor VIII / Q000032:analysis*; D006801:Humans; D055095:Optics and Photonics
chemical_list: D005169:Factor VIII