The testing of a symptomless population in order to detect cases of a disease at an early stage.
The basic principles of screening are:
- The condition is common and disabling, the natural history is known and that there is a recognisable latent or pre-symptomatic phase,
- The screening test is reliable, valid and repeatable, is acceptable and easy to perform, is sensitive and specific and low cost, and
- The treatment should be effective and available, and that there is an agreed policy on who to treat.