The probability that a medical test will detect the condition being tested for in people who actually have the condition. In other words, a sensitive test is one that produces true positive results. For example, the enzyme-linked immunosorbent assay (ELISA) HIV antibody test is highly sensitive, which means the test can detect HIV in most people infected with HIV. However, because the ELISA can sometimes mistakenly recognize antibodies to other diseases as antibodies to HIV (a false positive result), a Western Blot or other HIV test is used to confirm a positive ELISA HIV antibody test.