These are test that are done to detect an illness before it is clinically evident, where there is an effective treatment and where the benefits of the screening outweigh the costs (both financial and personal).
Screening tests find an illness before it occurs, for example:
- Pap smear finds cervical cancer before it is cancer
- Treating hypertension prevents there person from developing circulation problems, kidney and heart disease and strokes
Early detection testing finds a disease at a point before it is obvious by symptoms or physical findings AND there is a treatment that can be applied when the illness is found at an earlier stage that is more effective than when the treatment is not begun until a later stage. For example:
- Finding a cancerous polyp on a colonoscopy before it has spread into the wall of the colon or beyond
An age and gender-based list of recommended tests can be found here.