1. Medical College of Wisconsin, Milwaukee, Wisconsin, USA
2. Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
3. Detroit Medical Center University Laboratories, Detroit, Michigan, USA
4. McGill University Health Centre, Montreal, Quebec, Canada
5. Indiana University School of Medicine, Indianapolis, Indiana, USA
6. Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
7. Tricore Reference Laboratories, Albuquerque, New Mexico, USA
8. Wisconsin Diagnostic Laboratories, Milwaukee, Wisconsin, USA