1. Endocrinology and Diabetes Center, Yokohama Rosai Hospital, Yokohama, Japan
2. National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
3. Division of Clinical Hypertension, Endocrinology & Metabolism, Tohoku University Graduate School of Medicine, Sendai, Japan
4. Division of Nephrology, Endocrinology and Vascular Medicine, Department of Medicine, Tohoku University School of Medicine, Sendai, Japan
5. Department of Endocrinology, Metabolism and Nephrology, School of Medicine Keio University, Tokyo, Japan
6. Department of Endocrinology and Diabetes Mellitus, School of Medicine, Fukuoka University, Fukuoka, Japan
7. Department of Endocrinology and Metabolism, Rheumatology and Nephrology, Faculty of Medicine, Oita University, Yufu, Japan
8. Department of Community and Family Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan
9. Department of Endocrinology, Metabolism and Hypertension, National Hospital Organization Kyoto Medical Center, Kyoto, Japan
10. Reference Material Institute for Clinical Chemistry Standards, Kawasaki, Japan
11. Aska Pharma Medical Co., Ltd., Kawasaki, Japan