Screening tests Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Number of patients who need to be treated for ONE patient to benefit

A

Number needed to treat (NNT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Equation for NNT

A

NNT = 1 / ARR
(ARR = Risk(intervention) - Risk(control))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Number of patients who need to be treated for ONE patient to be harmed that would otherwise not have been harmed

A

Number needed to harm (NNH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

If NNT is negative, then it is this value

A

Number needed to harm (NNH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Attributable risk is called this when comparing benefits

A

Absolute risk reduction (ARR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Equation for risk reduction / attributable risk

A

Risk (no treatment) - Risk (treatment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Time period between disease onset and clinical symptoms that can be picked up by testing

A

Detectable preclinical period (DPCP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Validity test for screening test:
Identifying cases of disease

A

Sensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Validity test for screening test:
Identifying disease-free persons

A

Specificity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Validity test for screening test:
Person with a positive test has the disease

A

Positive predictive value (PPV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Validity test for screening test:
Person with a negative test does not have the disease

A

Negative predictive value (NPV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How to calculate sensitivity from 2x2 table

A

True positive / All disease positive (true positive + false negative)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How to calculate specificity from 2x2 table

A

True negative / All disease negative (True negative + false positive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How to calculate PPV from 2x2 table

A

True positive / All positive (true + false)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How to calculate NPV from 2x2 table

A

True negative / All negative (true + false)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Does PPV or NPV parallel changes in prevalence?

A

PPV

17
Q

Does PPV or NPV inversely parallel changes in prevalence?

A

NPV

18
Q

Tests used to rule out a diagnosis, have a high degree of sensitivity

A

Screening tests

19
Q

Tests used to rule in a diagnosis, have high degree of specificity

A

Confirmatory tests

20
Q

Screening tests have a high degree of this

A

Sensitivity

21
Q

Confirmatory tests have a high degree of this

A

Specificity

22
Q

How to calculate accuracy from a 2x2 table

A

(True negative + True positive) / Total

23
Q

How to calculate a positive Likelihood ratio from 2x2 table

A

Probability of true positive / probability of false positive

24
Q

How to calculate prevalence from 2x2 table

A

Disease positive / total

25
Q

How to calculate LR+

A

Sensitivity / (1 - specificity)

26
Q

How to calculate LR-

A

(1 - sensitivity) / Specificity

27
Q

Of the following, which can NOT be obtained from a 2x2 table:
Prevalence, incidence, sensitivity, specificity

A

Incidence