Diagnostic test interpretation

Question 1

What does validity mean?

Answer 1

Does the measurement reflect the status of what is being measured

Question 2

What does reliability mean?

Answer 2

Repeatability or reproducibility of a measurement

Question 3

How can you test the reliability?

Answer 3

Use an intra/inter assay or an interlaboratory test

Question 4

What does sensitivity mean?

Answer 4

Proportion with disease who test +ve

Question 5

What does specificity mean?

Answer 5

Proportion without disease who test -ve

Question 6

What does apparent vs true prevalence mean?

Answer 6

True +ve and false +ve VS true +ve and false -ve

Question 7

What does PPV mean?

Answer 7

Proportion of patients with positive tests who have the disease

Question 8

What does NPV mean?

Answer 8

Proportion of patients with negative test who don’t have the disease

Question 9

What three factors affect PPV and NPV?

Answer 9

Prevalence, sensitivity and specificity

Question 10

What is sensitivity and specificity of the SICCT tuberculin test like?

Answer 10

High specificity but low sensitivity