Factor VIII-related antigen (VIII R:AG) in haemophilic patients and in carriers.

All of fourteen patients with severe classic haemophilia and twelve of fifteen obligate carriers had a pre-peak ("rocket") above the sample well when factor VIII-related antigen was examined by crossed immunoelectrophoresis. The pre-peak may be found in other conditions--including von Willebrand's disease--but if these conditions can be excluded, the pre-peak may be helpful in identification of carriers or haemophilia.