hours Factor XIII 50–75 U with a half-life of 150–300 hours. von Willebrand factor 100–150 U with a half-life of 24 hours Cryoprecipitate also contains fibronectin; however there are no clear indications for fibronectin replacement. US standards require manufacturers to test at least four units each month, and the products must have a minimum of 150 mg or more of fibrinogen and 80 IU of factor VIII. Individual products may actually have less than these amounts as long as the average remains above these minimums. Typical values for a unit are substantially higher, and aside from infants it is rare to transfuse just one unit. History While the method for the creation of Cryo was discovered by Judith Graham Pool from Stanford University in 1964, it was initially approved in 1971 by the U.S. Food and Drug Administration under the name Cryoprecipitated AHF for the Hoxworth Blood Center University of Cincinnati Medical Center. References Blood products Transfusion medicine