Question

Comparing a new stool test with mucosal biopsy for diagnosing H. pylori, 400 patients were tested. Results show that 100 patients who tested positive for H. pylori infection on biopsy, 80 also tested positive with the new stool test. 120 patients who tested negative for H. pylori infection on biopsy, tested positive with the new stool test. What is the sensitivity of the new stool test?

A) 60%
B) 80%
C) 90%
D) 95%

Answer 1

The sensitivity of the new stool test for diagnosing H. pylori is 80%, as 80 out of the 100 patients who tested positive by biopsy also tested positive with the new stool test. Option B is the correct answer.

Step-by-step explanation:

To determine the sensitivity of the new stool test for diagnosing H. pylori, we look at the number of true positive results divided by the total number of actual positives as determined by the gold standard test, in this case, mucosal biopsy. Sensitivity essentially measures the test's ability to correctly identify those with the infection. In the given scenario, 100 patients tested positive for H. pylori by biopsy. Of these, 80 also tested positive with the new stool test. Thus, the sensitivity is calculated as (80 true positives) / (100 actual positives) = 0.80 or 80%.