When tested for hiv, how should a strongly positive elisa test (index above 7) and a negative western blot be interpreted? what additional testing is required?

Indetermined: Western blot is the confirmatory test if elisa is positive. I will repeat test in 4-6 weeks. In general if HIV test is negative and concerned about HIV then i will repeat it in 3 & 6 months. If negative after 6 months, then you dont have HIV infection, assuming you are not having possible exposure (i.e., sex, drug use, etc). If in doubt, then see id doctor.

Likely negative: This is probably a negative test. If the results haven't changed in a month, then you're definitely not infected. If you don't want to wait that long, you could get a viral load test. An undetectable viral load would be highly reassuring, but i'd still repeat the serology.