screening and diagnosis

Question 1

screening is used for ___

Answer 1

asymptomatic patients

Question 2

early detection is only helpful if ___

Answer 2

early intervention is available and helpful

Question 3

diagnosis is used for___

Answer 3

symptomatic patients

Question 4

diagnostic tests need higher levels of ___

Answer 4

precision and accuracy

Question 5

validity of test

Answer 5

how well does test measure what it is intended to

Question 6

reliability of test

Answer 6

repeated measurements yield same result

Question 7

what is a measure of reliability?

Answer 7

precision

Question 8

typical reference range

Answer 8

2 SD from the mean (derived from healthy patients)

Question 9

what increases the likelihood of an abnormal test?

Answer 9

increased number of tests performed

Question 10

define sensitivity

Answer 10

patients with disorder are positive

Question 11

SNOUT

Answer 11

tests with high sensitivity, a negative test can rule out

Question 12

sensitivity equation

Answer 12

true negative = sensitivity x all negatives

Question 13

define specificity

Answer 13

patients without disorder are negative

Question 14

SPIN

Answer 14

tests with high specificity, positive tests rule in

Question 15

specificity equation

Answer 15

true positives = specificity x all positives

Question 16

PPV

Answer 16

patients with disease test positive

Question 17

NPV

Answer 17

patients without disease test negative

Question 18

what is more reliable than predictive values?

Answer 18

likelihoods ratios

Question 19

3 reasons why gold standard tests aren’t always used

Answer 19

pose hazards, too costly, take too much time

Question 20

pre-test probability

Answer 20

probability that pt has disease before test is run

Question 21

pre-test probability is equal to

Answer 21

population prevalence

Question 22

if performing several tests, the ___ of the first becomes the ___ of the next

Answer 22

post-test probability; pre-test probability

Question 23

+LR equation

Answer 23

sensitivity/1-specificity

Question 24

-LR equation

Answer 24

1-sensitivity/specificity

Question 25

interpretation of LR greater than 1

Answer 25

post-test probability will be greater than pre-test probability

Question 26

interpretation of LR less than 1

Answer 26

post-test probability will be less than pretest probability

Question 27

interpretation of LR = 1

Answer 27

no difference in pre/post test probability

Question 28

to confirm disease, use test with high ___

Answer 28

specificity

Question 29

2 x 2 table equation for sensitivity

Answer 29

A/(A+C)

Question 30

2 x 2 table equation for specificity

Answer 30

D/(D+B)

Question 31

2 x 2 table equation for PPV

Answer 31

A/(A+B)

Question 32

2 x 2 table equation for NPV

Answer 32

D/(D+C)

Question 33

2 x 2 table equation for +LR

Answer 33

sensitivity/1-specificity

Question 34

2 x 2 table equation for -LR

Answer 34

1-sensitivity/specificity