Most doctors (General Practitioners) will do a regular blood work-up for your annual check-up, including cholesterol, white/red blood cell count, enzyme levels, and all that other jazz. They DO NOT check testosterone levels unless specifically requested and it adds about $100 to the bill.
When I asked my doc to check my test levels, he asked me why. I told that I was no longer aroused by him when he used his fingers to check my prostate. He told me those weren't fingers, and we moved on.