The criteria are based on the classic criteria first promulgated in a WHO Report in 1996, and also take into account international work on the appraisal of screening programmes, particularly that in Canada and the United States.1. The condition1.1 The condition should be an important health problem.1.2 The epidemiology and natural history of the condition, including development from latent to declared disease, should be adequately understood and there should be a detectable risk factor, disease marker, latent period or early symptomatic stage.1.3 All the cost-effective primary prevention interventions should have been implemented as far as practicable.2. The test2.1 There should be a simple, safe, precise and validated screening test.2.2 The distribution of test values in the target population should be known and a suitable cut-off level defined and agreed.2.3 The test should be acceptable to the population.2.4 There should be an agreed policy on the further diagnostic investigation of individuals with a positive test result and on the choices available to those individuals.3. The treatment3.1 There should be an effective treatment or intervention for patients identified through early detection, with evidence of early treatment leading to better outcomes than late treatment.3.2 There should be agreed evidence-based policies covering which individuals should be offered treatment and the appropriate treatment to be offered.3.3 Clinical management of the condition and patient outcomes should be optimised by all health care providers prior to participation in a screening programme.4. The screening programme4.1 There should be evidence from high quality Randomised Controlled Trials that the screening programme is effective in reducing mortality or morbidity.4.2 There should be evidence that the complete screening programme (test, diagnostic procedures, treatment/intervention) is clinically, socially and ethically acceptable to health professionals and the public.4.3 The benefit from the screening programme should outweigh the physical and psychological harm (caused by the test, diagnostic procedures and treatment).4.4 The opportunity cost of the screening programme (including testing, diagnosis and treatment) should be economically balanced in relation to expenditure on medical care as a whole.4.5 There should be a plan for managing and monitoring the screening programme and an agreed set of quality assurance standards.4.6 Adequate staffing and facilities for testing, diagnosis, treatment and programme management should be available prior to the commencement of the screening programme.4.7 All other options for managing the condition should have been considered (e.g. improving treatment, providing other services).