Factor V, wanda kuma aka sani da proaccelerin ko labile factor, furotin ne wanda ke taka muhimmiyar rawa a cikin tsarin daskarewar jini. Yana da haɗin gwiwa ga thrombin enzyme, wanda ke juyar da fibrinogen zuwa fibrin, furotin da ke haifar da aikin ɗigon jini. Ana samar da Factor V a cikin hanta kuma ana kunna shi ta hanyar thrombin don samar da factor Va. Yana daya daga cikin sunadarai masu yawa da ke cikin hadadden tsari na hemostasis, wanda shine tsarin jiki na dakatar da zubar jini bayan rauni. Maye gurbi a cikin kwayoyin halitta na Factor V na iya haifar da wani yanayi mai suna Factor V Leiden, wanda cuta ce ta gado wadda takan kara hadarin daskarewar jini.