Factor VIII and factor-VIII-related antigen in multiple myelomatosis and related conditions

Factor VIII and factor-VIII-related antigen (FVIIIRA) were estimated in 19 patients with paraproteinaemia. The FVIIIRA levels were above the normal range in 12 cases with II of these showing an abnormal FVIII/FVIIIRA ratio. The patients could be subdivied into three groups according to their FVIIIRA levels: normal levels, levels greater than normal but less than 200%, greater than 200%. This subdivision correlated with the degree of bone involvement as assessed by radiological skeletal survey.