A new tumor marker assay for prostate specific antigen (PSA) is evaluated for diagnostic sensitivity by testing serum samples from patients who have been diagnosed as having prostate cancer. The following results were obtained:
Number of prostate cancer patients who tested positive by the new assay = 42 out 46
Number of patients who did not have cancer and tested negative by the new assay = 31 out of 32
What is the sensitivity of the new assay for PSA?

Question

Quizplus · Accepted Answer

Sensitivity is calculated as the number of true positives divided by the total number of actual positives (true positives + false negatives). In this case, 42 out of 46 prostate cancer patients tested positive, so the sensitivity is (42/46) * 100 = 91.3%.

A New Tumor Marker Assay for Prostate Specific Antigen (PSA)