In the meantime, the TSH test range is still up for debate. Should we lower the TSH reference range as recommended, or shouldn't we? Everyone has their opinions, but what's the latest? Sadly, what we get is more evidence of confusion among endocrinologists, in the form of the article and accompanying editorial in the August 2008 issue of Clinical Thyroidology.
The article on "Lowering the thyrotropin reference limit to 2.5..." makes it clear that the mean and median TSH levels of the population without any thyroid dysfunction are under 2.0., and the percentage of the supposedly normal population who have a TSH level less than 2.5 is "only" 80%. Therefore, they reason, if the upper reference limit was lowered to 2.5, some 10-20% of the population in general (and 35% of those age 70 and above) who have a "normal" thyroid "might" be exposed many to unnecessary levothyroxine therapy.
Then, in an editorial, you have Martin Surks, MD weighing in on this, and explaining that the risk of progressing to hypothyroidism is increased in those who have antithyroid antibodies, adding that "since nearly 80% of subjects with TSH levels between 3.0 and 5.0 mIU/L do not have antithyroid antibodies, it is likely that the large majority of people with TSH in that range have little risk for the development of hypothyroidism."
Surks has been on this bandwagon before, and was apparently just as misguided back then. See my 2004 article Debate Over Subclinical Thyroid Disease Continues.
I theoretically understand the reluctance to change the official reference range. If you change it, then it nearly mandates treatment for anyone who falls outside that range. Why give treatment to those who don't need it? And, in some people, especially the elderly, unnecessary thyroid treatment may even cause additional health problems.
Endocrinologists will tell you that it's not all that rigid anyway, and that they use some common sense when evaluating people who are subclinical, and have the freedom to make judgments. But the truth is, most American's will never see an endocrinologist for their thyroid condition. There is such a shortage of endocrinologists that there is only one endo for every 40,000 Americans! Most of us see GPs, or family doctors, or internists. And what the endocrinologists just aren't understanding is that by leaving the reference range where it is, it becomes a rigid barrier of ignorance that most doctors use as their hard-and-fast rule for diagnosis and treatment.
Inability to make subtle diagnosis prevents patients who need it from getting thyroid treatment. For example, a woman with thyroid symptoms, a family history of thyroid problems, and a TSH of 4.5 may be adamantly refused thyroid treatment, and told by her family doc, ob-gyn or internist that her thyroid is "normal" because it's in the so-called normal range. Yet, if that woman is also trying to conceive, failing to treat her elevated TSH level may be the difference between infertility and/or miscarriage, and a healthy pregnancy.
What about the risk that these elevated subclinical TSH levels present for other conditions besides hypothyroidism? Conditions like heart disease, metabolic syndrome, high cholesterol, and more. Just last week, I reported on a study that found that women with TSH levels above 2.1 were at increased risk of Alzheimer's disease. Frankly, I'm fed up. Here is just a partial list of some of the articles about the risks of subclinical thyroid disease from here at the site. Each one of these articles cites respeced journals. Aren't these doctors reading?
- Should Doctors Treat Subclinical Hypothyroidism to Help Prevent Heart Disease?
- Normal TSH Levels Increase Risks of Fatal Heart Disease
- The Link Between Subclinical Hypothyroidism and Metabolic Syndrome
- Anxiety in Subclinical Thyroid Conditions
- Does Overt and Subclinical Hypothyroidism Complicate Pregnancy?
- Subclinical Hypothyroidism Treatment Reduces Heart Disease Risk
SHARE YOUR THOUGHTS!
What do you think the TSH normal range should be? Should it be the .3 to 3.0 that AACE and the laboratory experts recommended back in 2002? ( What are they waiting for already?) or should they keep it at 0.5 to 5.0. (After all, they shouldn't accidentally treat anyone, even if that means they refuse to treat millions.)