Find any hospital that takes anonymous tests. Most people hide the fact of blood donation for HIV. But if you are afraid in case of positive reaction, a visit to the regular clinic, but I have to visit a therapist or doctor to give you the direction to the analysis.
A few days refrain from foods rich in fats and sugars. Try not to eat anything that has animal origin. So you will achieve the exact result, but the analysis will take twice.
On the appointed day, give blood on an empty stomach and patience. Analysis for HIV infection is about two weeks, sometimes less. Don't worry, AIDS is not such a common infection, as it is said.