What can cause false positive ELISA HIV tests?

Unknown. There is not any real or valid answer to this. It is unknown. The only known reason would be previous participation in a specific HIV vaccine trial where some form of antibody response. But in one who have not so participated the answer is unknowable.

Related Questions

Would any form of ibd cause a false positive ELISA HIV test?

HIV testing. Inflammatory bowel diseases are a form of immune dysfunction, and as such can be considered a potential source of biologic false-positive results on tests that are very sensitive but non-specific. That is why confirmatory testing is needed. Read more...