Antibody tests are usually positive or negative, but sometimes they come back unclear. Tests that come back positive are redone to confirm they are right. Unclear results are repeated and if still unclear, different types of blood tests are done. If you get a positive test result and have no risk background (for example, blood transfusions or injecting drug use) it’s a good idea to check with your doctor to make sure that the blood laboratory double checked the result by using confirmatory tests.