these men have normal amounts of testosterone
available for use by the body but the serum testosterone level
is decreased. Saliva or urine test
results are considered a good representation of free hormone levels.
Because SHBG is known to be decreased in cases of hypothyroidism, obesity and acromegaly, and increased in hyperthyroidism and estrogen therapy, it is necessary to measure the free biologically-active testosterone in these conditions, when total testosterone can be misleading.