Screening

Question 1

reliability of a screeening test depends on __+__

Answer 1

repeatability of test (method variation)

repeatability of interpretation (observer variation)

Question 2

validity of a test depends on (4)

Answer 2

sensitivity
specificity
PPV
NPV

Question 3

proportion of people who don’t have the disease who tested negative =

Answer 3

specificity

Question 4

(-ve test given don’t have disease / total who dont have it ) x 100 =

Answer 4

specificity

Question 5

proportion of people who have disease and tested +ve =

Answer 5

sensitivity

Question 6

(+ve test given have disease / total who have disease)x100 =

Answer 6

sensitivity

Question 7

proportion who test +ve and have disease

Answer 7

PPV

Question 8

(have disease given tested +ve / total who tested +ve)x100 =

Answer 8

PPV

Question 9

proportion who test -ve and don’t have disease

Answer 9

NPV

Question 10

(don’t have disease given tested -ve / total who tested -ve)x100 =

Answer 10

NPV

Question 11

Must test screening test in __ as in ___ there is a higher prevalence of the disease because if is low prevalence really then most +ves won’t have disease even if sens and spec is high

Answer 11

community

not in outpatients

Question 12

Yield of screening test =

Answer 12

number of undiagnosed cases picked up by screening

Question 13

Wilson and Jungner’s criteria for screening = (7)

Answer 13

common+/serious condition
well defined latent period
suitable test with high spec+sens
effective treatment option
early detection = better prognosis
harm of test is low
cost effective