1. Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
2. Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
3. Department of Laboratory Medicine, Enshu Hospital, Hamamatsu, Shizuoka 430-0929, Japan
4. Department of Family and Community Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
5. Department of Internal Medicine, Kuma Hospital, Kobe, Hyogo 650-0011, Japan