What is appropriate bloodwork?
Dr. Karram: Do you obtain blood work before initiating testosterone treatment? If so, what tests do you order and what testosterone levels are considered to be normal for premenopausal and postmenopausal women?
Dr. Streicher: Unlike estrogen, which is predictably low in a postmenopausal woman, serum testosterone (T) levels are highly variable because of the adrenal component. Ovarian testosterone production does not cease at the same time as estrogen production. So I do obtain total and free T levels, prior to initiating treatment. Having said that, it has been well established that T levels correlate poorly with level of sexual interest, and there is no specific blood level that can be used to differentiate women with and without sexual dysfunction. We all have patients who have nonexistent T levels and have a very healthy libido, and other women with sky-high levels who have no libido. But it is useful to know levels prior to initiating therapy to be able to monitor levels throughout treatment. Also, if levels are in the premenopausal physiologic range, not only is she unlikely to respond but she is also at risk for developing androgenic adverse effects, such as acne and hair growth. In general, a low free T level (even if it is in the normal postmenopausal range) in a clinical setting of HSDD supports supplementation.
The assessment and interpretation of T levels can be challenging, particularly as the majority of testosterone is protein-bound and biologically inactive. Free T levels (the biologically active testosterone) in many labs are unreliable and need to be calculated.
In addition to total and free T, I check levels of sex hormone-binding globulin (SHBG), the protein that binds testosterone and renders it biologically inactive. If someone has high SHBG levels and is taking an oral estrogen, simply switching to a transdermal estrogen will result in decreased SHBG and increased free T.
Levels of total and free T vary from lab to lab, so it is best to be familiar with those ranges and then be consistent in which lab you choose.
Dr. Glaser: Although I personally do order blood work on most patients (T, free T, estradiol, complete blood count, thyroid-stimulating hormone, and follicle-stimulating hormone), after 15 years of research and publishing data on testosterone implants, I do not believe that T levels are absolutely necessary or even beneficial in most cases. It rarely changes management in my patients.
As Lauren said, it is well known that T levels do not correlate with androgen deficiency symptoms or clinical conditions caused by androgen deficiency. If a patient has symptoms of androgen deficiency, a trial of testosterone therapy should be given.
T levels are not a valid marker of tissue exposure in women, reflecting less than 20% of total androgen activity. The major source of testosterone in pre and postmenopausal women is the local intracrine production of testosterone from the adrenal precursor steroids dehydroepiandrosterone (DHEA) and androstenedione, which would not be reflected in T levels.
In our study involving 300 women, we found no relationship between baseline T levels, presenting symptoms, or response to therapy.6 Premenopausal and postmenopausal women had similar baseline T levels and similar response to therapy. Even women with baseline T levels in the mid-range responded to therapy.
Some of the most controversial topics in treating women with testosterone are related to dosing and T levels throughout therapy. Guideline authors often use the terms ‘physiologic dosing’ and ‘physiologic ranges’ when making recommendations for therapy. Although “physiologic” sounds appropriate/ scientific, these rigid opinions/recommendations are not evidence based. There are no data supporting the use of endogenous T ranges to guide dosing or monitor testosterone therapy.
The decision to initiate testosterone therapy is a clinical decision between the doctor and the patient based on the patient’s symptomatology, which is the therapeutic endpoint. Testosterone therapy must be done with adequate doses determined by clinical effect (benefits) versus side effects or adverse events (risks). T levels may be helpful, along with clinical evaluation when troubleshooting.
Utilizing data from thousands of patients, we have developed serum ranges for testosterone implants.11 Even so, no two patients are the same, nor do they respond to therapy the same. It is always a clinical decision.
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