Health Screening

Screening, in medicine, is a strategy used to look for as-yet-unrecognised conditions or risk markers in individuals without signs or symptoms. This testing can be applied to individuals or to a whole population. The defining features of screening programmes are that the people tested do not have signs or symptoms and the implied promise is future risk reduction from an undesirable disease outcome. As such, screening tests are somewhat unusual in that they are offered to and performed on persons apparently in good health.

Screening interventions are designed to identify conditions which could at some future point turn into disease, thus enabling earlier intervention and management in the hope to reduce mortality and suffering from a disease. Although screening may lead to an earlier diagnosis, not all screening tests have been shown to benefit the person being screened; overdiagnosis, misdiagnosis, and creating a false sense of security are some potential adverse effects of screening. Additionally, some screening tests can be inappropriately overused. For these reasons, a test used in a screening program, especially for a disease with low incidence, must have good sensitivity in addition to acceptable specificity.

Several types of screening exist: universal screening involves screening of all individuals in a certain category (for example, all children of a certain age). Case finding involves screening a smaller group of people based on the presence of risk factors (for example, because a family member has been diagnosed with a hereditary disease). Screening interventions are not designed to be diagnostic, and often have significant rates of both false positive and false negative results.