Most doctors don't measure testosterone levels. Historically, it just hasn't been part of the standard health panel of drug tests, but it damn well should be.
If they do measure testosterone levels, however, they'll almost always measure something called "total testosterone," which is, as the name implies, a measurement of the total amount of testosterone flowing through your veins.
The numbers might range anywhere from 300 to 1100 (nanograms per deciliter of blood). The trouble is, it tells you almost nothing about your hormonal status. For one thing, blood values of testosterone vary by the minute.
The only way to get a reasonably accurate reading would be to collect urine over a 24-hour period and have the lab use it to measure testosterone and its metabolites. Alternately, you could donate at least three blood samples from different times of the day. The lab would then pool the samples together and test that sample.
But those ways are more expensive, more time consuming, and more inconvenient. And even if you did pool multiple blood samples, it still wouldn't tell you much. For one thing, even though the results might indicate that you have a "normal" level of testosterone, it might not be normal for you.
Or maybe you had a reading of 1,000 in your twenties, but now you're getting by on a comparatively low level of 400. While 400 is considered normal, it might not be an optimum level for you. The only way you'd know what was normal for you is if you'd established a testosterone baseline reading before you turned 30, but hardly anybody does that.
Then there's the issue of steroid hormone binding globulin, or SHBG. It's what's called a glycoprotein and it literally binds up the sex hormones, including, on average, about 60% of your testosterone, and that percentage keeps climbing as you grow older.
The more SHBG you have, the more of your testosterone is bound up, leaving less of it free to do all the good stuff. So while your testosterone level may be as high as 600, a good portion of it could be locked up.
That's why, at the very least, when trying to determine your testosterone levels, doctors should ask the lab for your.
- Total testosterone levels
- "Free" testosterone levels
- "Bioavailable" testosterone levels
That way you can get a little bit better of an idea of what your testosterone situation is. Determining normal T levels is tricky, so regardless of what your lab values are, and given the problematical nature of the lab tests, you have to instead rely on symptoms and the simple desire to be more than you are, hormonally speaking.