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STUDY: TSH level between 3.0 and 5.0 uU/ml ...should be considered suspect.
ABSTRACT: Major Reversal at American Association of Clinical Endocrinologists Regarding TSH Levels and Diagnosing Hypothyroidism
COMMENTARY: In what constitutes a fairly dramatic reversal of its previous doctrine regarding how hypothyroidism should be diagnosed, the American Association of Clinical Endocrinologists (AACE) has said that:
"Even though a TSH level between 3.0 and 5.0 uU/ml is in the normal range, it should be considered suspect since it may signal a case of evolving thyroid underactivity."
This is the first time a conventional U.S. medical organization has acknowledged that the upper half of the TSH test's normal range may not in fact be normal, but rather, evidence of developing hypothyroidism, or a level that is potentially able to cause hypothyroidism symptoms in patients.
The conventional endocrinology doctrine has, for several decades, dictated that a TSH level that is in the so-called "normal range" indicate a "euthyroid" -- or normal -- state for the thyroid, and thus does not warrant treatment, despite clinical symptoms.
In fact, most patients who have numerous clinical symptoms of hypothyroidism, as well as a family history of thyroid disease -- and even those who have tested positive for the presence of thyroid antibodies indicative of autoimmune Hashimoto's Disease -- are declined treatment by endocrinologists and other physicians unless TSH levels are elevated above the laboratory's "normal range" -- which is typically a TSH level anywhere from 4.7 to 6.0 uU/ml.
Many people who are suffering thyroid symptoms. . . may now be considered hypothyroid and eligible to be diagnosed and treated.
The AACE's acknolwedgement lags years behind the efforts of a number of pioneering physicians and patient advocates -- as well as what patients themselves have suspected.
Almost four years ago, for example, Dr. A P Weetman, a professor of medicine, wrote in the article "Fortnightly review: Hypothyroidism: screening and subclinical disease" which appeared in the 19 April 1997 issue of the British Medical Journal, the following groundbreaking statement:
". . . even within the reference range of around 0.5-4.5 mU/l, a high thyroid stimulating hormone concentration (>2 mU/l) was associated with an increased risk of future hypothyroidism. The simplest explanation is that thyroid disease is so common that many people predisposed to thyroid failure are included in a laboratory's reference population, which raises the question whether thyroxine replacement is adequate in patients with thyroid stimulating hormone levels above 2 mU/l."
"Why are we following a test which has no correlation with clinical presentation? The thyroidologists by consensus have decided that this test is the most useful for following treatment when in fact it is unrelated to how the patient feels. The consequences of this have been horrendous. Six years after their consensus decision Chronic fatigue and Fibromyalgia appeared. These are both hypothyroid conditions. But because their TSH was normal they have not been treated. The TSH needs to be scrapped and medical students taught again how to clinically recognize low thyroid conditions."
Other physicians have been working with antibodies testing to evaluate thyroid function, and in some cases treating patients with normal range TSH values who had thyroid antibodies evident of the autoimmune disease process.
Elizabeth Vliet, MD, who runs the popular women's health centers, Her Place and who is author of the bestselling book, Screaming to be Heard: Hormonal Connections Women Suspect...and Doctors Ignore, has never believed that TSH tests are the indicator of a woman's thyroid health. Since the mid 1990s, Dr. Vliet has been saying that symptoms, along with elevated thyroid antibodies and normal TSH, may be a reason for treatment with thyroid hormone. Here's a quote from her book:
"The problem I have found is that too often women are told their thyroid is normal without having the complete thyroid tests done. Of course, what most people, and many physicians, don't realize is that...a 'normal range' on a laboratory report is just that: a range. A given person may require higher or lower levels to feel well and to function optimally. I think we must look at the lab results along with the clinical picture described by the patient...I have a series of more than a hundred patients, all but two are women, who had a normal TSH and turned out to have significantly elevated thyroid antibodies that meant they needed thyroid medication in order to feel normal. This type of oversight is particularly common with a type of thyroid disease called thyroiditis, which is about 25 times more common in females than males...a woman may experience the symptoms of disease months to years before TSH goes up..."
The current TSH levels used by laboratories to define the "normal" range of thyroid function, and the use of the TSH test as primary means of diagnosis need to be significantly reevaluated. The .5 to 5.5 "normal range" for thyroid function is just not enough information for diagnosis anymore.
Research reported in the British Medical Journal found that TSH levels above 2 are likely not normal, and instead include people at high risk to develop thyroid disease. This means that the real "normal range" is probably far narrower, and more concentrated in the lower end of the range.
New studies need to be conducted to look at this issue comprehensively, evaluating the true normal range for a population of individuals who have no thyroid antibodies, and who do not ever go on to develop thyroid disease in their lifetimes.
In February of 2000, a groundbreaking study estimated that as many as 13 million Americans had undiagnosed thyroid disease. The vast majority of these people would be women, suffering from undiagnosed hypothyroidism. This Colorado Thyroid Disease Prevalence Study used the standard diagnostic criteria to define hypothyroidism -- that the TSH had to exceed the lab's normal range, which for the purposes of this study, was 5.1 uU/ml. Broadening the lab diagnostic criteria then, to levels above 3 would mean that the Colorado Thyroid Disease Prevalence Study suggests that many more than 13 million Americans are likely to be defined as hypothyroid.