It should have no effect. If the
screening method for HIV can be effected from
alcohol and throw back a false-positive (because I am not familiar if the test is effected by that or not, but I highly doubt that it is), the lab would run a confirmatory test anyways, and the confirmatory tests would only look for the HIV RNA in your body, not anything else. Which means: Either way, you will get an accurate result, regardless of alcohol consumption.