The tsh test and normal tsh level controversies gas questions

Using the typical reference range, a TSH under 0.5 (a low TSH) may be indicative of hyperthyroidism (an overactive thyroid), and a TSH over 4.5/5.0 (a high TSH) may indicate hypothyroidism (an underactive thyroid.) The TSH Reference Range Controversy

One of the most controversial issues has been the issue of the changing "normal" reference range for the TSH test. In late 2002, the National Academy of Clinical Biochemistry (NACB) issued new guidelines for the diagnosis and monitoring of thyroid disease.

In the guidelines, the NACB reported that the TSH reference range was too wide and actually included people with thyroid disease. When more sensitive screening was done, which excluded people with thyroid disease, 95 percent of the population tested had a TSH level between 0.4 and 2.5. As a result, the NACB recommended reducing the reference range to those levels.

The NACB guidelines led to a recommendation in January 2003 by the American Association of Clinical Endocrinologists (AACE), calling for doctors to "consider treatment for patients who test outside the boundaries of a narrower margin based on a target TSH level of 0.3 to 3.0." The statement also said: "AACE believes the new range will result in proper diagnosis for millions of Americans who suffer from a mild thyroid disorder, but have gone untreated until now."

In research published in the Journal of the American Medical Association in 2003, Dr. Vahab Fatourechi and fellow researchers estimated that if the range were narrowed according to the AACE recommendations, the total number of people with thyroid disease would expand from approximately 5 percent of the population to an estimated 20 percent of the population, with most of the added patient population falling in the hypothyroid/underactive category.

At the same time, however, a consensus conference made up of representatives from the key professional groups involved in thyroid treatment—including the American Association of Clinical Endocrinologists, the American Thyroid Association, and the Endocrine Society—published their findings in 2004, recommending against routine treatment of patients with TSH levels of 4.5 to 10.0 mIU/L. The new reference range initiative was dropped.

Almost two decades later, America’s testing laboratories still use the old reference range of and doctors remain divided. Among conventional physicians, most continue to refuse to diagnose hypothyroidism unless the TSH test results are outside the traditional reference range and flagged as abnormal by the laboratory.

Jeffrey Garber, MD, FACE, addressed the controversy on behalf of the American Association of Clinical Endocrinologists (AACE). According to Dr. Garber, guidelines are not meant to function as a replacement for the judgment of a physician’s individual practice. While in his published writings, Dr. Garber has said he doesn’t feel that treating subclinical hypothyroidism is typically warranted, he said that in practice, he doesn’t hesitate to treat a patient with a TSH within the reference range if he judges it to be potentially helpful.

Said Garber, "The TSH normal range should not be a polarizing issue. But as often seen in medicine, it’s easier to agree on the extremes. When you get closer to what’s marginal, it’s a harder call. We need to realize that it’s a continuum. If people know that this particular group is more likely to have thyroid disease than the group that’s lower, it doesn’t commit you to treatment and doesn’t say that it’s not appropriate, it says to follow it, and maybe intervene." The Challenge for Patients: “Your TSH Is Normal”

When your doctor gets your test report back, anything within the reference range will not be flagged as abnormal. That means, if your doctor relies on flagged levels and only acts on levels outside the reference range, you will not be diagnosed or have your treatment adjusted.

When faced with endocrinologists or other physicians who are reluctant to diagnose by any other means than a rigid interpretation of the TSH results, it may be time to get a second opinion from an endocrinologist, or broaden your search to include a holistic MD, osteopathic physician, or a trained and licensed naturopath.

• Clinical evaluation of your visible signs of thyroid disease, including changes in reflexes, swelling and edema of your face and extremities, hair loss in head and body, loss of outer edges of eyebrows, thyroid enlargement, eye changes, heart rate, blood pressure, and other measurable signs

Garber, J, Cobin, R, Gharib, H, et. al. "Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association." Endocrine Practice. Vol 18 No. 6 November/December 2012.