I’ve been told that salivary tests are more reliable than blood tests. What’s your opinion? J.W.

Salivary tests are valuable in assessing tissue levels of certain hormones such as estrogen, progesterone, testosterone, and cortisol. This is advantageous since tissue levels reflect the amount of hormone that is actually being delivered rather that the amount that is being transported in the bloodstream. Salivary hormone levels are ideally suited to evaluate sex hormone balance. They are not adequate to assess other situations, such as thyroid disease, in which other factors including antibody levels may play a role, nor are salivary tests able to measure the level of other substances in the body.  -Dr. Peterson