How is testosterone deficiency diagnosed?

History and Labs: History indicates this may be present. Any male suffering fatigue and having erectile dysfunction should have testosterone levels. I like to use both total testosterone and free testosterone levels to verify deficiency. I also get a psa (prostate cancer blood test) to make sure prostate cancer is not present prior to starting testosterone replacement in someone proven to need it.

Blood test: If you have the symptoms, then blood tests will likely confirm a low testosterone. One word of caution, if you have a very high sex hormone binding globulin level, you will still have symptoms of low t even though your total t is normal.