1. Department of Central Laboratory, Kumamoto University Hospital, 1-1-1, Honjo, Kumamoto 860, Japan
2. Faculty of Pharmaceutical Sciences, Kumamoto University, 5–1, Oe-honmachi, Kumamoto 862, Japan
3. Department of Laboratory Medicine, Kumamoto University, School of Medicine, 1-1-1, Honjo, Kumamoto 860, Japan