1. Department of Clinical Laboratory Science, Chungbuk Health & Science University, Cheong-ju 363-794, Korea
2. Department of Clinical Laboratory Science, Dong-eui University, Busan 614-714, Korea
3. Department of Preventive Medicine, Chungbuk National University College of Medicine, Cheongju 362-763, Korea
4. Department of Laboratory Medicine, Chungbuk National University College of Medicine, Cheongju 362-763, Korea