1. Department of Chemical Pathology, University of Cape Coast School of Medical Sciences, Cape Coast, Ghana
2. Department of Haematology, University of Ghana Medical School, Accra, Ghana
3. Department of Medicine, University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
4. Department of Haematology, Korle-Bu Teaching Hospital, Accra, Ghana
5. Haematology Unit, Tamale Teaching Hospital, Tamale, Ghana