Chapter 30 Principles of disease screening
Screening for a disease means searching for evidence of that disease among asymptomatic individuals. The aim of screening is to detect a disease at an early stage, when treatment is associated with an improved outcome (i.e. a better chance of survival from the disease) compared with the outcome if a patient presented with symptoms of the disease.
The requirement for a significant impact on the population means that the disease should be common and/or associated with serious consequences for affected individuals. The biological progression of the disease is important; in particular, a presymptomatic phase must exist during which the early disease process can be identified by a suitable screening test. Tests must have a high degree of: