Testosterone Deficiency     The Hidden Disease      
by E. Barry Gordon, M.D.

Print This Page


Testosterone Blood Tests

If you decide to have your blood tested to determine your testosterone blood level, be aware of the four pitfalls that could prevent you from getting an accurate and meaningful result.

1. "Normal" is not the same as "sufficient".

2. There are two basic types of testosterone blood tests.

        The total testosterone measures all testosterone in the blood, most of which is bound to protein. It is inactive and does nothing.

        The free testosterone (also called unbound or bioavailable) is the actual active hormone, and is the only worthwhile test.

3. Many laboratories report different ranges of "normal" for different age groups. The lower ranges are actually a reflection of the worsening of the disease of testosterone deficiency as we grow older, and certainly not desirable. Pay attention only to the highest (youngest) range.

4. In addition to the above, the so-called "normal" ranges or "reference" ranges as listed by all the laboratories I've had contact with are incorrect. The lower limit of their ranges are either too low, ridiculously too low, or absent altogether.

5. In view of all this DO NOT accept a statement from your doctor's office that, "Your testosterone level is normal". Determine it for yourself. You need to get just two numbers. Your free testosterone level, and the upper limit of the range for the youngest age group for that laboratory. Divide this upper limit number by 2.7 and take that number to be the lower limit of sufficiency. If your value is less than that you are most likely deficient in testosterone.

        Several studies have been published recently supporting the proposition that current laboratory reference ranges are erroneous and misleading.

                  Testosterone Test Study 1
                      Harvard Medical School   2006
                          "Laboratory reference values for testosterone ..... are established without clinical considerations."

                  Testosterone Test Study 2
                      European Journal of Endocrinology   2007
                          "In men older than 70 years, total testosterone remains stable while free testosterone declines with age."

                  Testosterone Test Study 3
                      Clinical Chemistry   2007
                          "The decrease of BT (free testosterone) in older men is more pronounced than the decrease in total testosterone."

Medical Studies