Diagnostic tests

Question 1

What is diagnostic sensitivity?

Answer 1

Frequency of test being correctly positive

= TP / TP + FN

Question 2

What is diagnostic specificity?

Answer 2

Frequency of test being correctly negative

= TN / TN + FP

Question 3

What is diagnostic accuracy?

Answer 3

Frequency of correct diagnosis

= TP + TN / TP +FP +TN + FN

Question 4

What is the predictive value of a positive test?

Answer 4

Liklihood of a positive test result meaning a correct diagnosis

= TP / TP +FP

Question 5

What is the predictive value of a negative test?

Answer 5

Liklihood of a negative test results meaning no disease

= TN / TN + FN