6.1 and 6.2 Screening

Question 1

What is spontaneous presentation?

Answer 1

Person presents with symptoms and a diagnosis is made

Question 2

What is opportunistic case finding?

Answer 2

Person presents with symptoms related to a problem and HCP takes opportunity to check for other conditions

Question 3

What is a diagnosis?

Answer 3

Definitive identification of a suspected disease or defect

Question 4

What is screening?

Answer 4

Systematic attempt to detect an unrecognised condition. Screening uses a simple test which is very quick to do. If positive, the person is described as screen positive. More tests must be done before a diagnosis is made

Question 5

What is the main purpose of screening?

Answer 5

To give a better outcome to the patient than if they spontaneously presented

Question 6

Describe the criteria for a screening programme with regard to the disease

Answer 6

Important health condition
Epidemiology well understood
Must have an early detectable stage
Must consider primary prevention first

Question 7

Describe the criteria for a screening programme with regard to the test

Answer 7

Needs to be simple, safe, precise, valid and acceptable to the population
Agreed cut off level for who to investigate further

Question 8

Describe the criteria for a screening programme with regard to the treatment

Answer 8

The condition must be treatable and early detection must be advantageous

Question 9

Describe the criteria for a screening programme with regard to the programme

Answer 9

The programme must have the facilities required for diagnosing, treating and counselling.
The benefit needs to outweigh the harm from the test or the treatment.

Question 10

What is a false positive?

Answer 10

Non-cases who test positive

Question 11

What is a false negative?

Answer 11

Case who test negative

Question 12

What is sensitivity of a screening test?

Answer 12

The proportion of people who really have the disease and test positives.
True positives/ All with disease

Question 13

What is specificity of a screening test?

Answer 13

The proportion of people who do not have the disease and test negatively
True negatives/ All without disease

Question 14

What is positive predictive value in a screening test?

Answer 14

Probability that someone who has tested positive has the disease
True positive/ All positives

Question 15

What is negative predictive value in a screening test?

Answer 15

The proportion of people who test negatively and who actually do not have the disease
True negative/ All negatives

Question 16

How does screening effect the doctor-patient relationship?

Answer 16

Doctor invites patients in rather than spontaneous presentation. Offered help for a condition they may not even have known about

Question 17

What is lead-time bias?

Answer 17

A screening programme looks like it is prolonging life but patients actually just know they have the disease for longer. They still die at the same time

Question 18

What is length-time bias?

Answer 18

Screening programmes are better at picking up slow acting diseases which are likely to have favourable prognoses.

Question 19

What is selection bias in a screening programme?

Answer 19

Skewed by healthy-worker effect. People likely to go to screenings are also likely to have other positive health promotions.

Question 20

Give 3 negatives of screening

Answer 20

Carries potential harms
People treated unnecessary
Need to communicate harms and risks well
Growing attention to extent of overdiagnosis

Question 21

Give 4 social critiques of screening

Answer 21

Victim blaming
Individualising pathway
Increased surveillance of population 
Females targeted more than men 
Non-attendance is seen as 'deviant'