[1] Univ Orange Free State, Fac Hlth Sci, Dept Internal Med, Div Clin Haematol, Bloemfontein, South Africa
[2] Univ Orange Free State, Pathcare Labs, Bloemfontein, South Africa
[3] Univ Orange Free State, S African Natl Blood Serv, Bloemfontein, South Africa
[4] Univ Orange Free State, Fac Hlth Sci, Dept Haematol & Cell Biol, Bloemfontein, South Africa
[5] Univ Orange Free State, Dept Psychol Educ, Bloemfontein, South Africa
[6] Univ Orange Free State, Fac Hlth Sci, Off Dean, Div Hlth Profess Educ, Bloemfontein, South Africa