Screening

Screening is defined as ‘the examination of asymptomatic people in order to classify them as likely or unlikely to have a disease’.¹ Screening is undertaken to detect early disease in apparently healthy individuals. The WHO has produced guidelines for the effectiveness of screening programs.² These guidelines, and those of the National Health Service (NHS) in the UK,³ have been kept in mind in the development of recommendations about screening in the Red Book, as detailed below.
 
Condition

• It should be an important health problem.
• It should have a recognisable latent or early symptomatic stage.
• The natural history of the condition, including development from latent to declared disease, should be adequately understood.

• It should be simple, safe, precise and validated.
• It should be acceptable to the target population.
• The distribution of test values in the target population should be known and a suitable cut-off level defined and agreed.

• There should be an effective treatment for patients identified, with evidence that early treatment leads to better outcomes.
• There should be an agreed policy on who should be treated and how they should be treated.

• There should be evidence of improved mortality, morbidity or quality of life as a result of screening, and the benefits of screening should outweigh the harm.
• The cost of case finding (including diagnosis and treatment of patients who are diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole.

• Consumers should be informed of the evidence so they can make an informed choice about participation in screening programs.

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A sixth program, the National Lung Cancer Screening Program, will commence in 2025.