• Colorectal cancer screening
• guaiac test

Colorectal cancer screening with tests that identify occult blood in faeces are currently the cornerstone of the screening programmes in most developed countries.1 The first generation of this class of tests has been proven in several randomised controlled trials to significantly reduce mortality from colorectal cancer when performed every 1–2 years after the age of 50 years.2–5 It has further been shown to be associated with reduced incidence of colorectal cancer, presumably due to additional detection of premalignant lesions.6 However, the old school of faecal occult blood tests (FOBTs), even though proven effective, suffers from less than optimal sensitivity and leaves much to be desired in terms of improved detection qualities. Newer faecal-based tests can be divided into three groups: (1) guaiac tests of higher sensitivity, such as Hemoccult Sensa; (2) high-sensitivity immunological tests and (3) stool-based genetic tests.7 8 Of these, the genetic tests are still at relatively early stages of development and scientifically are not ready yet for prime-time use, in spite of some recent suggestions in this direction.9–11 Both newer techniques of the detection of faecal occult blood, sensitive guaiac and immunological tests, have been demonstrated in several studies to have a sensitivity rate which is at least twice higher than the old generation tests …