1. MedStar Health Research Institute, MedStar Washington Hospital Center, Washington, District of Columbia, USA.
2. Faculty of Medicine, University of Medicine, Tirana, Albania.
3. Department of Laboratory Medicine, NIH Clinical Center, Bethesda, Maryland, USA.
4. Department of Laboratory Medicine, Mount Sinai Hospital NY, New York, New York, USA.
5. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.