Can i drink black coffee before blood work that requires a 12 hour fast?

Fasting: Yes. Of course. Every primary care specialist will advise you to avoid calories when you are fasting. So water and black coffee are the two things that are allowed. Every office I have worked at tells their patients this when they are told to fast prior to coming in for these lab tests.

No: Fasting requires no food and no beverages (water may be allowable). Coffee contains caffeine ; other chemicals that can enter your blood stream. Drinking black coffee can skew some laboratory tests. It is not a true 12 hour fast if you drink coffee.