what does borderline reaction mean in an HIV test result

This term is sometimes used by people to describe the situation of having a positve ELISA test followed by an "indeterminate" Western blot. The Western blot is a serologic test that shows antibody reactions to various antigens associated with HIV. A strongly positive Western blot occurs when there are reactions against several different HIV antigens. Sometimes a Western blot shows an incomplete reaction to 1 or 2 antigens and is considered indeterminate. This can happen for a variety of reasons, like being tested shortly after HIV exposure. Usually, these types of test results can be clarified by retesting at a later date or using an alternative test or correlating the results with other information, like history and symptoms.