Diagnostic test/prev/incid Flashcards

1
Q

Sensitivity definition?

A

the probability of a diseased person testing positive

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2
Q

Specificity definition?

A

the probability of a non-diseased person testing negative

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3
Q

PPV definition?

A

the probability that person who has a positive test, actually has the disease

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4
Q

NPV definition?

A

the probability that person who has a negative test, actually does not have the disease

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5
Q

Positive likelihood ratio definition?

A

a ratio representing the likelihood of having the disease given a positive result

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6
Q

Negative likelihood ratio definition?

A

a ratio representing the likelihood of having the disease given a negative result

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7
Q

sensitivity formula?

A

TP/ (TP+FN)

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8
Q

specificity formula?

A

TN/ (TN+FP)

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9
Q

PPV formula?

A

TP/ (TP+FP)

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10
Q

NPV formula?

A

TN/ (TN+FN)

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11
Q

+LR formula?

A

Sensitivity/ (1-specificity)

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12
Q

-LR formula?

A

(1-sensitivity)/ specificity

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13
Q

Sensitive tests have many ….

A

FP

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14
Q

Specific tests have few ….

A

FP

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15
Q

SN-N-OUT?

A

sensitive tests, if negative, rule out the disease

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16
Q

SP-P-IN?

A

specific tests, if positive, rule in the disease

17
Q

sensitivity. value approaching 100 proc. is desirable for ruling OUT DISEASE and indicates a low FN rate

18
Q

specificity. value approaching 100 proc. is desirable for ruling IN DISEASE and indicates a low FP rate

19
Q

What test for screening?

A

sensitivity

20
Q

what test used for confirmation after a positive screening test?

A

specificity

21
Q

increasing prevalence of disease increases ……

A

PPV

PPV varies directly to prevalence

22
Q

decreasing prevalence of disease increases ……

A

NPV

NPV varies inversely to prevalence

23
Q

LR +/- ranges?

A

LR+ > 10 and/or LR- <0,1 indicate a very usedul diagnostic test

24
Q

Incidence. definition?

A

Measure of NEW cases that develop in a population over a certain period of time

25
Prevalence. definition?
Measure of the TOTAL number of cases (new and old) measured at a particular point in time
26
Incidence. 2 points to remember?
2. Measuring incidence: a. Make sure you define the TIME PERIOD during which new cases is counted b. Make sure you include only the population at risk of acquiring the disease
27
prevalence incr --> PPV?
incr
28
prevalence decr --> PPV?
decr
29
prevalence incr --> NPV?
decr
30
prevalence decr --> NPV?
incr
31
Precision (reliability)? patikimumas. definition?
The consistency and reproducibility of a test. Absence of random variation in a test
32
Accuracy (validity)? pagrįstumas. definition?
the trueness of test measurement. The absence of systematic erroc or bias in test. It means how much the test results agree with the gold standard test.