1. Information Services Division , NHS National Services Scotland , Edinburgh, Scotland , UK
2. Centre for Research into Cancer Prevention and Screening , University of Dundee, Ninewells Hospital and Medical School , Dundee, Scotland , UK
3. Department of Blood Sciences and Scottish Bowel Screening Laboratory , Ninewells Hospital and Medical School , Dundee, Scotland , UK
4. Scottish Bowel Screening Laboratory , Ninewells Hospital and Medical School , Dundee, Scotland , UK
5. Department of Gastroenterology , Ninewells Hospital and Medical School , Dundee, Scotland , UK