1 Donor Services Division, South African National Blood Service, Johannesburg, South Africa. Electronic address: [email protected].
2 Technical Services Division, South African National Blood Service, Johannesburg, South Africa.
3 Medical Division, South African National Blood Service, Johannesburg, South Africa.
4 Medical Division, South African National Blood Service, Johannesburg, South Africa; Division of Clinical Haematology, Department of Medicine, University of Cape Town, Cape Town, South Africa; Division of Clinical Haematology, University of the Free State, Bloemfontein, South Africa.
5 Western Cape Blood Service, Cape Town, South Africa.