screening

Question 1

is it normal to be screened in the uk

Answer 1

no it is rare

Question 2

what is screening

Answer 2

a process which sorts out apparently well people who probably have a disease (or precursors or susceptibility to a disease) from those who probably do not

Question 3

is screening intended to be diagnostic

Answer 3

no

Question 4

types of prevention

Answer 4

primary prevention
secondary prevention
tertiary prevention

Question 5

main purpose of screening

Answer 5

secondary prevention
detect early disease to alter the course of the disease

Question 6

what does screening want to achieve

Answer 6

• reduce the risk of developing disease
• provide treatment
• provide information

Question 7

define sensitivity

Answer 7

the proportion of people with the disease who are correctly identified by the screening test

Question 8

define specificity

Answer 8

the proportion of people without the disease who are correctly excluded by the screening test

Question 9

define positive predictive value

Answer 9

the proportion of people with a positive test result who actually have the disease

Question 10

define negative predictive value

Answer 10

the proportion of people with a negative test result who do not have the disease

Question 11

what are predictive values dependent on

Answer 11

underlying prevalence
whereas sensitivity and specificity are not

Question 12

what is screening criteria based on

Answer 12

wilson and jugner criteria

Question 13

what is the wilson and jugner criteria for the condition

Answer 13

1. the condition should be an important health problem
2. the natural history of the condition should be well understood
3. there should be a detectable early stage

Question 14

what is the wilson and jugner criteria for the treatment

Answer 14

1. there should be an accepted treatment for patients with recognised disease
2. facilities for diagnosis and treatment should be available
3. adequate health service provision should be made for the extra clinical workloud resulting from screening

Question 15

what is the wilson and jugner criteria for the test

Answer 15

1. a suitable test should be devised for the early stage
2. the test should be acceptable
3. intervals for repeating the test should be determined (not a one off)

Question 16

what is the wilson and jjugner criteria for the risks and benefits

Answer 16

1. there should be an agreed policy on whom to treat
2. the costs should be balanced against the benefits
3. the risks, both physical and psychological, should be less than the benefits

Question 17

3 types of biases

Answer 17

selection bias
lead-time bias
length-time bias

Question 18

what is selection bias

Answer 18

people who choose to participate in screening programmes may be different from those who do not

Question 19

describe breast cancer screening

Answer 19

eligible group - women
test - 2 view mammography
further tests - mammography, biopsy, ultrasound, cytology
treatment - surgery, radiotherapy, chemotherapy
avoiding - overall deaths in screened women

Question 20

5 types of screening

Answer 20

1. population based screening programmes
2. opportunistic screening
3. screening for communicable diseases
4. pre employment and occupational medicals
5. commercially provided screening