Case Finding and Screening

Question 1

Define Screening

Answer 1

Test on people not known to have disease

• Differentiates between people who are healthy but have disease from those who are disease free*
• E.g. Sending faecal tests for prostate cancer to over 50 year olds*

Question 2

Define Case Finding

Answer 2

Systematic search for at risk individuals and targeting resources at them rather than waiting for them to develop disease

Sending faecal tests for prostate cancer to men over 50, with history of cancer and low fibre diet

Question 3

What are the 10 WHO guidelines on the principles of screening

Wilson and Junger classic screening criteria

Answer 3

1. The condition sought should be an important health problem.
2. There should be an accepted treatment for patients with recognized disease.
3. Facilities for diagnosis and treatment should be available.
4. There should be a recognizable latent or early symptomatic stage.
5. There should be a suitable test or examination.
6. The test should be acceptable to the population.
7. The natural history of the condition, including development from latent to declared disease, should be adequately understood.
8. There should be an agreed policy on whom to treat as patients.
9. The cost of case-finding (including diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole.
10. Case-finding should be a continuing process and not a “once and for all” project.

Question 4

Define Senstivity

Answer 4

The ability to detect disease (true positive)

Question 5

Define Specificity

Answer 5

The ability to rule out disease (true negative)

Question 6

How do yu calculate a screening tool’s sensitivity and specificity

Answer 6