Final answer:
The Enzyme immunoassay is the test that indicates the presence of Hep C antibodies, which requires a confirmatory test if positive to ensure an accurate diagnosis.
Step-by-step explanation:
The nurse should identify the Enzyme immunoassay as the test indicating the presence of Hep C antibodies. This test, often part of a serological hepatitis panel, is specifically designed to detect the antibodies that the immune system produces in response to the infection. If the initial enzyme immunoassay is positive, a confirmatory test, such as a test for hepatitis C viral RNA, is required to rule out a false-positive result and confirm the diagnosis.