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Flashcards in Screenings in Medicine Deck (24):
1

True Positive

Test correctly reports a positive result in a patient that acutes DOES have the disease

2

True Negative

Test correctly reports negative result in a patient DOES NOT have the disease

3

False Positive

Test incorrectly reports a positive result in a patient that actually DOES NOT have the disease

4

False Negative

Test incorrectly reports a negative result in a patient that actually DOES have the disease

5

Sensitivity

How well a test can detect presence of disease when in fact disease is PRESENT... Positivity of test in the Diseased

6

A sensitive test has a low false negative rate

Proportion of time that a Test is positive in a patient that DOES have the disease

7

Sensitivity calculation

Sensitivity= TP/(TP+FN)x100%

8

Specificity

How well a test can detect absence of disease when in fact the disease is absent ..... negativity of test in the healthy

9

A specific test has a low false positive rate

Proportion of time that a test is NEGATIVE in a paitent that does not have the diesease

10

Specificty calculation=

Specificity=TN/(TN+FP)x100%

11

Positive Predictive Value(PPV)

How accurately a positive test predicts the presence of diesee. Percentage of TP's in patients with a positive test (correct predition)

12

PPV=

TP/(TP+FP)x100%

13

Negative Predicitive Value

How accurately a negative test predicts the absence of diease.. Percentage of TN's in patinents with a negative test ( Correct predition)

14

NPV=

NPV=TN/(TN+FN)x100%

15

Daignostic Accurace(DA) or Diagnositc Precision(DP)

Proportion of time that a patient is correctly identified as either having a diesase or not having a diesase with a positive or negative test

16

DA/DP=

=(TP+TN)/(TP+FP+FN+TN) x 100%

17

Likelihood Ratios

Probablity of a given test result for a person with the disease / probabiltiy of the same test reslut for a person without the diesase.... can be done for positive or negative

18

LR+..... should be >10 to demonstrate the test is most beneficial

Probabilty of a positive test in the presence of diesease/ probabilty of a positive test in the absence of diesase.... sensitivity/(1-specificity(C BOX))

19

LR-... should be <0,1 to demonstrate that the test is most beneficial

Probabilty of anegative test in the presnence of diesase /probabilty of a negative test in the absence of disease
= (1-sensitivity)/specificity

20

a useless test

a test that gives you equal probablity of having a negative or positive test

21

Validity

ability to accurately discern btw those that DO have the disease and those that DONOT have the disease "telling the truth"

22

Internal validity

extent to which results accurately reflect the true situation of the study population (sample)

23

external validity

extent to which results are applicaple to other populations not included in the original study (how similar were study participants to your patients?)... generalizability

24

Reliability

ability of a test to give the SAME results on repeated uses... reproducability/ consistency.... A valid test is always reliable, yet a reliable test is not always valid