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."
