5 - Diagnostic and Screening Tests

Question 1

Prior Disease Probability 1%

Low Morbidity & Mortality

Answer 1

No Treat

Question 2

Prior Disease Probability 90%

High Morbidity & Mortality

Answer 2

Treat

Question 3

Prevalence

Answer 3

(All Disease +) / Total Sample

Question 4

Sensitivity

Answer 4

True Positive / All Disease

= TP/(TP+FN)

Question 5

Specificity

Answer 5

True Negative / All Disease

=TN/(FP+TN)

Question 6

Positive Predictive Value

Predictive Value Positive (PVP)

Answer 6

True Positive / All Who Test +

=TP/(TP+FP)

Question 7

Bayes’ Theorem

Answer 7

Pretest Odds x Likelihood Ratio = Post-test Odds

Question 8

Odds

Answer 8

P/(1-P) where P = Probability

Question 9

LR+

Answer 9

Sensitivity/(1-Specificity)

Question 10

LR-

Answer 10

(1-Sensitivity)/Specificity