Preventive Medicine, Health Promotion and Screening
Preventive medicine and screening tests the criteria for worthwhile screening, immunisation, lifestyle counselling and risk-based prevention. The exam expects you to distinguish evidence-based screening from opportunistic testing and to discuss harms.
Core rules
- A screening programme needs an important condition, accepted treatment, a detectable latent stage, a suitable test, adequate follow-up and acceptable cost and harm.
- Screening is offered to asymptomatic people; diagnostic confirmation follows a positive screen.
- Immunisation schedules should be checked at every contact; catch-up is preferable to restarting.
- Brief behaviour change counselling uses clear advice, risk communication and follow-up.
- Overdiagnosis and false positives are real harms, not mere inconvenience.
- Risk communication uses absolute risks and natural frequencies.
Worked example
A 52-year-old woman asks for a “full body scan”. The reasoning: she is asymptomatic, and whole-body imaging is not a validated screening programme. Assess her actual risk: breast screening according to national policy, cervical screening history, colorectal screening if eligible, blood pressure, smoking, weight and family history. Explain benefits, harms and uncertainty, and arrange appropriate tests rather than ordering indiscriminate imaging. Document the shared decision.
Traps
Ordering tumour markers as screening; calling a positive screening test a diagnosis; vaccinating during a mild illness unnecessarily; omitting lifestyle advice because medication was prescribed; and screening without informed choice.