Assays of von Willebrand Factor Antigen and Ristocetin Cofactor Activity; Approved Guideline<\/p>\n","protected":false},"excerpt":{"rendered":"
Abstract NCCLS document H51-A\u2014Assays of von Willebrand Factor Antigen and Ristocetin Cofactor Activity; Approved Guideline is part of a series of guidelines that address methods in hemostasis testing. The assay of ristocetin cofactor is the most common single test used in the diagnosis of von Willebrand disease and its classification into different subtypes. It is a functional assay of von Willebrand factor activity that measures the ability of the antibiotic ristocetin to induce platelet agglutination in the presence of von Willebrand factor. Thus, the rate and extent of platelet agglutination is a function of the concentration and functional integrity of von Willebrand factor. Determination of von Willebrand factor antigen is another common single test used in the diagnosis of von Willebrand disease and its classification into numerous subtypes. The method described allows the quantitation of von Willebrand factor antigen (protein) by an enzyme-linked immunosorbent assay (ELISA). This guideline describes appropriate test specimens, reagents and materials, methods of platelet agglutination and ELISA, preparation of reference curves, determination of reference intervals, quality control procedures, result interpretation, and sources of error for assays of von Willebrand factor antigen and ristocetin cofactor activity. A brief description of von Willebrand disease and its various subtypes is included, as well as a list of references to more comprehensive reviews of this commonly inherited and rarely acquired bleeding disorder. NCCLS. Assays of von Willebrand Factor Antigen and Ristocetin Cofactor Activity; Approved Guideline. NCCLS document H51-A (ISBN 1-56238-473-2). NCCLS, 940 West Valley Road, Suite 1400, Wayne, Pennsylvania 19087-1898 USA, 2002.<\/p>\n","protected":false},"featured_media":1947,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_cat":[26],"product_tag":[],"yoast_head":"\n