Lecture 33 - Screening

Question 1

What is screening?

Answer 1

the widespread use of a simple test for a disease in an
asymptomatic population

Question 2

What is a screening test?

Answer 2

• usually relatively cheap
  and simple
• used to test large numbers of
  asymptomatic people to identify early disease
• will then go on to have further diagnostic tests to confirm the diagnosis

Question 3

What do we need to consider for screening?

Answer 3

• Seriousness of disease
• Ability to alter course of disease
• Lead time
• Prevalence of pre-clinical disease

Question 4

Screening is an example of what type of prevention?

Answer 4

secondary

Question 5

When does the Prevalence of pre-clinical disease not matter when considering screening?

Answer 5

• Serious disease
• Cheap and easy to administer test

Question 6

What is lead time?

Answer 6

The time between detectable disease and symptoms

Question 7

What is sensitivity for testing?

Answer 7

Proportion of people with the
disease who test positive

Question 8

What is specificity for testing?

Answer 8

Proportion of people without the disease who test negative

Question 9

What influences predictive values?

Answer 9

influenced by disease
prevalence

Question 10

What is a positive predictive value?

Answer 10

Proportion of people who test
positive and have the disease

Question 11

What is a negative predictive value?

Answer 11

Proportion of people who test negative and don’t have the
disease

Question 12

What are the harms of screening programmes?

Answer 12

1. Increases in health inequities
2. Physical
3. Psychological
4. False positives
5. Financial