A standard blood test usually just tests for vitamin levels, white blood counts, hormone levels, etc. If they make you "fast" (not eat anything before the blood test) they will also be checking for blood glucose levels.
The doctor can add anything extra that he feels the need to test for like aids or other stds, but that's not usually part of a standard blood workup.
It's your blood, so you can ask what they are testing for. The lab should be able to tell you.
