1. Department of Internal Medicine, Seoul Saeroun Internal Medicine, Seoul, Korea.
2. Department of Preventive Medicine, Eulji University School of Medicine, Daejeon, Korea.
3. Seoul Clinical Laboratories, Seoul, Korea.
4. Department of Pediatrics, Park Hee Bong Pediatrics, Seoul, Korea.
5. Department of Internal Medicine, Neane Internal Medicine, Seoul, Korea.
6. Department of Pediatrics, Yoon Bo Young Seoul Pediatrics, Seoul, Korea.
7. Department of Pediatrics, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea.
8. Department of Internal Medicine, Bucheon St. Mary's Hospital, The Catholic University of Korea, Bucheon, Korea.
9. Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.