Final answer:
The serological test where a confirmatory test is used to override a screening result is the test for HIV I & II. The initial positive result from screening tests, such as the ELISA, is confirmed using a more specific test like the Western blot or RT-PCR. Option C is correct.
Step-by-step explanation:
For what serological test may a confirmatory test be used to override a screening test result? The answer is c. HIV I & II. When initial screening tests for HIV, such as the indirect ELISA, yield a positive result, confirmatory tests are required due to the possibility of false positives, which may occur because of cross-reactivity with antibodies directed against other antigens.
The commonly used confirmatory test for HIV is an immunoblot (western blot) or a nucleic acid test (NAT), like reverse transcriptase PCR (RT-PCR). These tests are more specific and can confirm the presence of the virus by detecting its peptides or genetic material.
A confirmatory test may be used to override a screening test result in HIV I & II. The initial screening test for HIV is an indirect ELISA assay, which detects the presence of anti-HIV antibodies. However, a positive result from the screening test must be confirmed using a more specific and accurate test, such as an immunoblot or nucleic acid antigen test, to definitively diagnose an HIV infection.