At HealthCheck USA, you can have a variety of medical tests run for yourself, bypassing your doctor's office (and that expense). Many people do this periodically, as a general check on their physical health.
HealthCheck gives information with the lab results, as well as providing a physician's service to answer any additional questions. And, of course, if anything unusual pops up, you can (and should) take the test results to your physician. As an added convenience, you can get your results online, and print them out. No prescription is necessary.
You can check for diabetes ($25), as well as your cholesterol levels ($37), and if you're pregnant ($93). There's an entire series of tests for heart health that are combined under the name Gabe Merkin, which is offered in conjunction with Dr. Merkin's bestselling book, The Healthy Heart Muscle, for those who are following his program.
They offer other test combinations, as well (men's health; women's health; cancer screenings; etc). DNA testing is even available, to screen for possible genetic illnesses (such as Celiac disease or Hemochromatosis).
There are too many tests to mention, the complete list is shown at their site.
Personal note: I learned about this company, which started in San Antonio, when the local grocery chain, HEB Foods, offered their services in the store pharmacies. This was a couple of years back and I signed up for a basic batch of tests. The cost was reasonable, and now I have a baseline to check my health against periodically. The cost was reasonable, the convenience was great, and the same lab was used as the one my doctor prefers.