A new assay is used to test 120 samples from patients with a clinically confirmed diagnosis of the relevant infection and 50 samples from healthy control subjects.The test results were positive for 90 of the infected patients and positive for 10 of the healthy controls.
-Calculate the assay's specificity.

Question

Quizplus · Accepted Answer

Specificity is calculated as the number of true negatives divided by the total number of actual negatives (true negatives + false positives). In this case, the true negatives are the healthy controls who tested negative, which is 40 (50 total healthy controls - 10 false positives). The total number of actual negatives is the total number of healthy controls, which is 50. Therefore, specificity = (40/50) * 100 = 80%.

A New Assay Is Used to Test 120 Samples from Patients