Part 2: Disease Detection

Suppose a new rapid screening test is being developed to detect a disease. Patients who take the new test also take an older test to confirm the results. The older test is 100% accurate, but since it is slower and more invasive, it is not a good choice for testing the general population. It is estimated that the new test has a sensitivity of 97% and a specificity of 95%.

11. Consider a population of 50,000 patients where a 25% disease prevalence is assumed. Fill in the missing numbers in the breakdown below based on the use of the new test. (6 x 2 pt = 12 pt) Population 50,000 a. Number of Infected People b. Number of Healthy People 25% of Population 75% of Population c. Number of Positive d. Number of e. Number of Positive f. Number of Test Results Negative Test Results Test Results Negative Test Results (97% of Infected Get (3% of Infected Get a (5% of Healthy Get a (95% of Healthy Get a a Positive Result) Negative Result) Positive Result) Negative Result) True Positives (TP) False Negatives (FN) False Positives (FP) True Negatives (TN)