Overview
Introduction
Screening starts with a defined population, not with a disease label.
Screening starts with a defined population, not with a disease label. It looks for a condition before recognized symptoms appear, using a program justified by the condition's importance, a recognizable presymptomatic stage, an acceptable and sufficiently accurate test, and evidence that earlier treatment improves outcomes. A positive screen is a signal for follow-up; it is not a diagnosis. Neurologic screening programs illustrate why the population and the purpose of the test matter. US newborn bloodspot screening is based on the federally recommended Recommended Uniform Screening Panel (RUSP), but each state determines its implemented panel. Newborn hearing screening follows the CDC Early Hearing Detection and Intervention 1-3-6 benchmarks. In contrast, the USPSTF recommends against screening asymptomatic adults for carotid artery stenosis and finds evidence insufficient for several other asymptomatic programs, including cognitive impairment, atrial fibrillation, and autism spectrum disorder in the specified age group. These recommendations do not apply when symptoms or concerns are present; a concern changes the task from population screening to clinical assessment. Prevention is not the same as screening. Daily folic acid reduces, but does not eliminate,...