Normally a urine test (they take two samples about half an hour apart) but they will also draw blood if you are under suspicion or a winner of a world championship or whatever. They do that to test for a variety of things that urine won't do, such as, are your testosterone molecules natural or plant based (testosterone powders are made from yams). They may also take multiple blood samples through the year to check on any fluctuations. Not sure, but maybe they need blood to detect some substances, but don't quote me on that.