What are possbilities for why the ELISA results after done several times keeps on doing false positi

Scenario: The patient does not have HIV confirmed by conducting the Western Blot and RT-PCR. But why when conducting the ELISA the patient's test results continuously comes back positive? What are possibilities?

The ELISA test is usually done initially and if the test is positive then the Western blot is done to confirm/deny the positive result.

A negative Western Blot = Negative for HIV.

many other disease conditions 鈥?such as leprosy, malaria, leishmaniasis and other viral infections 鈥?give rise to false positive results in the ELISA test without the concomitant HIV infection. Furthermore, many of the conditions that cause a false positive result in the ELISA test are conditions that are also prevalent in many of the recognised AIDS risk groups. A great deal of scientific data indicate widespread non-specific interactions between what are considered retroviral antigens and unrelated antibodies. A positive HIV ELISA test may also indicate previous antigenic stimulation by other retroviral infection. Another concern is that there is no precedent for the diagnostic utilisation of the ELISA test for other viral diseases. In general, the presence of antibodies specific to a particular disease is a major indicator of potential immune protection by the body, which is not the case with HIV infection, since antibodies to HIV fail to confer any immunoprotection against HIV.

The ELISA test may therefore not be a true indicator of infection but an artefact arising from cross reactivity of other naturally occurring viral proteins.