Is elisa test for hiv1 &2 after 4 months of potential exposure (with no exposure in between) conclusive? any further tests required ?

More test needed: The algorithm is: Elisa + then repeat Elisa, if positive again we need confirmation through a Western Blot test, if that is positive as well is confirmatory of HIV, if any of those are negative but the first Elisa + we need to re check 3-6 weeks later or order a PCR or antigenP24 study. 4 months should be good enough, if Elisa is negative after that time there is no need to re test.