Test Characteristics

Question 1

False positive

Answer 1

Test is positive, patient has no disease

Question 2

False negative

Answer 2

Test is negative, patient has disease

Question 3

Sensitivity of test

Answer 3

Proportion of those with disease which it correctly identifies
true positives / (true positives + false negatives)

Question 4

Specificity of test

Answer 4

Proportion of those without disease which it correctly identifies
true negatives / (true negatives + false positives)

Question 5

Positive predictive value

Answer 5

Probability that subject has the disease given that they have a positive result
true positives / (true positives + false positives)

Question 6

Another way of defining PPV

Answer 6

PPV = sensitivity x prevalence / sensitivity x prevalence + ((1-specificity) x (1-prevalence))

Question 7

Negative predictive value

Answer 7

Probability that a subject does not have the disease given that they have a negative result
true negatives / (true negatives + false negatives)

Question 8

Diagnostic test

Answer 8

To confirm or exclude the presence of a disease

Question 9

Screening test

Answer 9

To asses the risk of disease in an asymptomatic person to determine the need for further confirmatory diagnostic testing

Question 10

Prognostic test

Answer 10

To asses the risk of future displease and the need for preventive measures