1. Department of Chemical Pathology, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa (R.H., J.A.G.)
2. Division of Endocrinology and Metabolism, Department of Internal Medicine, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.)
3. Division of Lipidology, Hatter Institute for Cardiovascular Research in Southern Africa, Department of Medicine, University of Cape Town, Cape Town, South Africa (D.J.B.).