1. Southern Iron Disorders Center, Birmingham, Alabama.
2. Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota.
3. Section of Biostatistics, Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina.
4. Division of Gastroenterology, Department of Medicine, London Health Sciences Centre, London, Ontario.
5. Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama.