Atlanta Men’s Clinic performs a simple and quick blood test to check testosterone levels. The test only takes a few minutes and will be performed by one of our qualified medical professionals. The low side of man’s normal total testosterone range is about 300 nanograms per deciliter (ng/dL). The upper limit for testosterone levels is around 800ng/dL depending on the lab. When looking at testosterone levels adjusted for age, you’ll see that a young man near the bottom of the current reference range is very much below average.