screening programmes- sally

Question 1

What is the definition of screening programmes?

Answer 1

‘the use of simple tests across an apparently healthy population in order to identify individuals who have risk factors or early stages of disease, but do not yet have symptoms.’ (WHO)

Question 2

What is the detailed definition of screening programmes?

Answer 2

‘the process of identifying individuals who may be at higher risk of a disease or condition amongst large populations of healthy people. Once identified, those individuals can consider further tests, and healthcare providers can offer them interventions of benefit. A screening programme needs to offer more benefit than harm, at a reasonable cost to the NHS.’ (Public Health England)

Question 3

What is recommended for screening?

Answer 3

• breast cancer
• cervical cancer
• bowel cancer
• chlamydia
• abdominal aortic aneurism
• antenatal screening (Down’s syndrome)
• neonatal screening (hearing)
• diabetic retinopathy

Question 4

What is NOT recommended for screening?

Answer 4

• bladder cancer
• lung cancer
• oral cancer
• prostate cancer
• thyroid cancer
• diabetes

Question 5

List 3 reasons why screening should be carried out.

Answer 5

1. look for evidence of disease in asymptomatic individuals
2. earlier detection = better chance of successful treatment
3. may be more cost effective

Question 6

Is screening always possible?

Answer 6

No!

Question 7

What does the UK National Screening Committee do?

Answer 7

Meets 3 times a year to consider or reconsider evidence for screening programmes

Question 8

What is the criteria for appraising the viability, effectiveness, and appropriateness of a screening programme?

Answer 8

• the condition
• the test
• the treatment
• the programme

Question 9

What factors should be considered regarding the CONDITION?

Answer 9

• should be an important health problem
• natural history of the condition should be adequately understood
• a detectable risk factor or disease marker
• a latent period or early symptomatic stage
• cost-effective primary prevention interventions should have already been implemented

Question 10

What should be considered regarding the screening TEST?

Answer 10

• must be simple, safe, precise and validated
• distribution of test values in target population should be known
• suitable cut point should be defined
• acceptable and understandable to target population
• agreed policy on further diagnostic procedures and choice in event of positive result

Question 11

What is sensitivity?

Answer 11

ability to detect a disease when it IS present

Question 12

What is specificity?

Answer 12

ability of a test to correctly identify the absence of disease

Question 13

What is the positive predictive value?

Answer 13

TP/ TP+FP

% of positive test results, in a given population that have been tested, that are actually correct

Question 14

What is the negative predictive value?

Answer 14

TN/ TN+FN

% of negative test results, in a given population that have been tested, that are actually correct

Question 15

What are the factors to be considered regarding the TREATMENT?

Answer 15

• there should be an effective treatment for patients identified through early detection
• there should be evidence to show that early treatment leads to better outcomes than late treatment

Question 16

What are the factors to be considered regarding the PROGRAMME?

Answer 16

• evidence from randomised controlled trials to show programme reduces mortality or morbidity
• evidence that the test used accurately measures risk/disease
• evidence that the programme is clinically, socially and ethically acceptable to health professionals and the public
• benefits of programme should outweigh the physical and psychological harm that may be caused
• cost of programme should be economically acceptable
• programme must be properly managed
• adequate quality assurance standards must be in place