Health Promotion and Preventive Medicine

Primary prevention acts before disease begins. Immunization, tobacco prevention, safer alcohol use, and folic acid before conception reduce the chance that disease or harm develops in the first place. Secondary prevention looks for disease or risk in a person without symptoms. FIT for colorectal cancer, HPV-based cervical screening, blood pressure measurement, lipid assessment, and bone mineral density testing belong here. A screening test is useful only when there is a detectable preclinical phase, the test is acceptable, and earlier treatment improves outcomes enough to outweigh harm. Tertiary prevention limits disability after disease is established. Cardiac rehabilitation after myocardial infarction and complication surveillance for diabetes are examples. The category matters because it determines the clinical task. A person with rectal bleeding needs diagnostic evaluation, not routine colorectal screening. A person with a breast mass needs diagnostic imaging, even if they are younger than the organized screening program’s entry age. Screening schedules do not create permission to defer assessment of symptoms.