Hypothyroidism and TSH Levels: References
See also the TSH Levels page.
Purpose of this compilation
To show that using only the TSH (thyroid stimulating hormone) level as a diagnostic tool does not identify many cases of hypothyroidism, and that if it is used, the current acceptable range is to be questioned. These findings come from Europe and North America.
I. Medical Journals and Organizations
A. The American Association of Clinical Endocrinologists
"Thyroid Awareness Month: 2001"
Click here (AACE) for the full text.
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.
B. British Medical Journal
1. "Thyroid function tests: time for a reassessment" by Denis St. J. O'Reilly, consultant clinical biochemist (Scotland)
2000;321:1080 (28 October)
Click here (BMJ 1) for the full text.
Overlap between the statistically derived normal and abnormal ranges is accepted in diagnostic tests, giving rise to false positive and false negative results. These concepts have not been applied to measurements of thyroid stimulating hormone. Rather than accepting that the test can be fallible, we transfer the problem to the patient.
O'Reilly's response to the letters about his article
Click here (BMJ 1a) for the full text.
…the clinical features of thyroid dysfunction are now rarely discussed in the medical literature and…as a consequence, the impression is given that they are of little importance.
2. "Thyroxine should be tried in clinically hypothyroid but biochemically euthyroid patients" by Gordon R. B. Skinner, Clinical virologist, R. Thomas, General practitioner, M. Taylor, General practitioner, M. Sellarajah, General practitioner, S. Bolt, General practitioner, S. Krett, General practitioner, A. Wright, General practitioner (England)
1997;314:1764 (14 June) Letters
Click here (BMJ 2) for the full text.
We wish to question present medical practice, which considers abnormal serum concentrations of free thyroxine and thyroid stimulating hormonethose outside the 95% reference intervalto indicate hypothyroidism but incorrectly considers "normal" free thyroxine and thyroid stimulating hormone concentrations to negate this diagnosis….
The…thyroid stimulating hormone concentrations in 80 patients considered to be hypothyroid on established criteria indicated that…only four patients had thyroid stimulating hormone values above the reference interval of 0.5-5.5 mU/l…the mean concentration of thyroid stimulating hormone was 2.2 (0.4) mU/l….
Responses to the above BMJ letter
David Derry (Canada), MD, PhD
Click here (BMJ 2a) for the full text.
The maxim of the day before the TSH arrived was you gave enough thyroid until the patient was better…medical students are taught to treat a lab test and not the patient. This has gone a long way to alienate the patient from the doctor and seek alternative practices for relief.
E. H. McLaren, Consultant physician, C. J. G. Kelly, Specialist registrar in endocrinology, M. A. Pollock, Principal biochemist (Scotland)
Click here (BMJ 2b) for the full text.
Since they [patients] complained of a considerable reduction in their quality of life, which had not been helped by other measures, we decided that it was justifiable to try treating two of them with 100 µg thyroxine daily (after we had explained the lack of scientific rationale and obtained their written consent). Much to our surprise, they both reported a considerable improvement in their condition, while the results of thyroid function tests remained within the reference range….
Response to the above BMJ letter
Nikki Tovell (England), informed patient, currently co-authoring a paper with Dr B. Durrant-Peatfield, 21 June 2000
Click here (BMJ 2c) for the full text.
Drs McLaren, Kelly and Pollack quite rightly state that it is arrogant of the medical profession to assume that everything is known about the thyroid. Currently, hypothyroid testing commonly only addresses T4 and TSH levels.
3. "Hypothyroidism: screening and subclinical disease" by Dr. A. P. Weetman, professor of medicine (England)
...if a patient has signs and symptoms of illness and test results are negative, you aren't performing the right tests.
1997;314:1175 (19 April)
Click here (BMJ 3) for the full text.
...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.
Responses to the above BMJ article
Dr. David Derry (Canada), MD, PhD, 17 Oct. 1999
Click here (BMJ 3a) for the full text.
…there is no correlation except at extremes between the signs and symptoms of thyroid problems and the TSH….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….The TSH needs to be scrapped and medical students taught again how to clinically recognize low thyroid conditions.
Raymond Peat (US), independent research, 16 Nov. 1999
Click here (BMJ 3b) for the full text.
…the mistaken idea of hypothyroidism's low incidence in the population led to the acceptance of dangerously high TSH activity as "normal."
C. European Journal of Endocrinology
"High serum cholesterol levels in persons with 'high-normal' TSH levels: should one extend the definition of subclinical hypothyroidism?" by Georgia Michalopoulou, Maria Alevizaki, Gregory Piperingos, Demetrios Mitsibounas, Emily Mantzos, Panayotis Adamopoulos and Demetrios A Koutras of Athens University School of Medicine (Greece)
Click here (EJE) for the full text.
Subjects with high-normal TSH levels [2.0-4.0 µU/ml] combined with ThAabs [thyroid autoantibodies] may, in fact, have subclinical hypothyroidism presenting with elevated cholesterol levels. It is possible that these patients might benefit from thyroxine administration.
D. The Journal of Clinical Psychiatry
1. "Exaggerated TSH Responses to TRH in Depressed Patients With 'Normal' Baseline TSH" by Robert P. Kraus, F.R.C.P.(C), Elizabeth Phoenix, B.Sc.N., Merrill W. Edmonds, F.A.C.P., Ian R. Nicholson, C.Psych., Praful C. Chandarana, F.R.C.P.(C), and Sonya Tokmakejian, Ph.D., F.C.A.C.B. (Canada)
Click here (JCP 1) for the full text.
Subtle thyroid underfunction may be contributing to depression in some patients with TSH in the upper half of the range usually considered normal. If so, then the TRH-ST [stimulation test] may be more sensitive in identifying this than measurement of TSH alone.
2. "A Highly Successful Approach to Hypothyroidism" by John V Dommisse (US), MD, FRCPC
A summary was published in The Journal of Clinical Psychiatry in July 1993
Click here (JCP 2) for the full text.
…big double-myth is that (a) an elevated ultrasensitive-TSH level is always required before a diagnosis of hypothyroidism can be made; and that (b) its nearly-complete suppression always means that at-least-adequate treatment is in place.
II. Doctors’ Articles
1. "Suggestions for an Approach to the Management of Thyroid Deficiency" by Dr. Barry J.
Click here (Peatfield) for the full text.
That the diagnosis is all too frequently missed…is commonly the result of an
incomplete clinical appraisal in favour of the standard thyroid function tests.
These tests are the real problem in diagnostic failure since there are inherent
problems in interpreting blood levels of thyroxine and/or thyroid stimulating
hormone (TSH) when blood levels may differ widely from tissue blood levels. Since
the diagnosis may very properly, and easily, be made clinically, unreliable blood
levels should NOT take precedence over clinical judgment.
2. Dr. John C. Lowe (US): drlowe.com Most Recent Q&As
Click here (Lowe) for the full texts.
The TSH level is not well synchronized with the tissue metabolic rate. (Probably most doctors falsely assume that studies have shown that the TSH and metabolic rate are synchronized. But despite my diligently searching for years for such studies, I’ve yet to find them.) Adjusting the T4 dose by the TSH level is like adjusting the speed of your car by a speedometer that's out of synchrony with the actual speed of the car.
...patients fall into a bell curve regarding the amount of T4 (or T3) that suppresses their TSH levels. Patients also fall into a bell curve regarding how their thyroid glands respond to any particular blood level of TSH. In response to a TSH level that the typical conventional endocrinologist adores, the glands of some patients will release enough thyroid hormone to keep metabolism normal. In response to this same TSH level, the thyroid glands of other patients will release too little thyroid hormone to keep metabolism normal. These patients will remain ill with symptoms of slow metabolismdespite the same TSH level that keeps other patients well.
Despite the bravado of many lab test-obsessed endocrinologists, all tests that measure levels of T3, T4, and TSH suffer serious technical shortcomings. For example, a host of environmental, physiological, and disease factors can alter the levels. The level-altering effects of such factors often make diagnostic and treatment decisions based on the levels dubious and debatable. When a doctor isn’t aware that such factors have influenced hormone levels, his treatment decisions for a patient may be wrong and harmful. This is certainly true of the TSH test, which most endocrinologists seem to view as infallible.
3. "Thyroid Disease Far More Widespread Than Originally Thought, 13 Million May Be At Risk"
by Dr. Joseph Mercola (US), DO
Click here (Mercola / "widespread") for the full text.
4. "Optimum Diagnosis and Treatment of Hypothyroidism With Free T3 and Free T4 Levels"
by Dr. Joseph Mercola (US), DO
The study also found that even a slight decrease in thyroid functionwhat is sometimes referred to as "subclinical" or low-level hypothyroidismmay raise cholesterol levels. These findings are consistent with what was reported on by the American Association of Clinical Endocrinologists survey regarding cholesterol and thyroid disease in January of 2000. That study found that as many as ten percent of the 98 million Americans with high cholesterol levels may not know that their cholesterol is elevated due to undiagnosed thyroid problems.
The thyroid/heart disease/cholesterol linkage was further confirmed in the
February 15, 2000 Annals of Internal Medicine's publication of the Rotterdam Study
results. The Rotterdam study found that older women with subclinical
hypothyroidism were almost twice as likely as women without this condition to
have blockages in the aorta, and were also twice as likely to have had heart
…many people whose test results are dismissed as normal could continue to have
symptoms of an underactive thyroid.
Click here (Mercola / "optimum") for the full text.
Most patients continue to have classic hypothyroid symptoms because excessive reliance is placed on the TSH. This test is a highly accurate measure of TSH but not of the height of thyroid hormone levels.
The basic problem that traditional medicine has with diagnosing hypothyroidism is
the so called "normal range" of TSH is far too high: Many patients with TSH's of
greater than 1.5 (not 4.5) have classic symptoms and signs of hypothyroidism.
III. Interviews With Doctors by Mary Shomon
1. An Interview with Don "Doc Don" Michael (US), M.D., Dec. 2000: "Getting What You Need
from Your Doctor: Challenges of Thyroid Care"
Click here (Michael) for the full text.
Saying that your thyroid is healthy because your number is between the little
number and the big number is easily as foolish as claiming that you are physically
fit if your weight is between 75 and 260 pounds (That would probably cover 95.5%
of the weights in the USA.) without knowing anything else.
2. "Rethinking the TSH Test: An Interview with David Derry [Canada], M.D., Ph.D." July 2000
Click here (Derry) for the full text.
…many people would develop classic signs and symptoms of hypothyroidism but the TSH was ever so slow to become abnormal, rise and confirm the clinical diagnosis.
Sometimes it never did. Finally I began treat patients with thyroid in the normal
manner I was taught. I could not see why I had to wait for the TSH to rise for me to
be able to treat them.
3. An Interview with Joseph Mercola (US), DO, June 2000: "Hypothyroidism and the Role of Armour Thyroid, Seaweed, Exercise, and More..."
Click here (Mercola / "role") for the full text.
…most traditionally based physicians have long abandoned their physical
examination and diagnosis skills and appear unwilling to believe that patients who
complain of all the classic hypothyroid symptoms are in fact truly hypothyroid if
their TSH is normal. They would rather believe a lab test than the patient sitting in
front of them.
4. An interview with Dr. John Dommisse (US), MD, FRCP, in which he discusses treating
people with a TSH over 1, as well as the use of T3, Sept. 1999
Click here (Dommisse) for the full text.
I ran into too many patients who had classic hypothyroid symptoms, which cleared completely on appropriate thyroid treatment, and whose TSH was below 2.0 (but
above 1.5) and with FT4 and FT3 levels in the low ends of their 'normal
ranges'….Finally, I found some patients with several symptoms and signs of
hypothyroidism whose TSH was between 1.0-1.5; so I lowered my range, for the
last time, to 0.1-1.0; I now treat primary hypothyroidism with a TSH of >1.0 (if the
FT4 and FT3 are low-normal, not above the middle of their 'normal ranges').
IV. Other Websites
1. About.com Thyroid Disease Weblinks and News: "What is Normal TSH? Probably Somewhere Around 1.0!"
Click here (Weblinks) for the full text.
I work in a hospital lab and have done thousands of thyroid profiles. I've discovered that, while normal range for TSH is 0.5-5.0, the AVERAGE TSH for patients with no thyroid disease, is around 1.0!
2. Mary Shomon (US), author of About.com Guide to Thyroid Disease and Living Well With Hypothyroidism
"HELP! My TSH Is 'Normal' But I Think I'm Hypothyroid" 11/10/97
Click here ("normal") for the full text.
In my own experience, I feel downright awful at anything above 4, and I feel great between 1 and 2, which is where my endocrinologist keeps my TSH. But some
doctors would have no problem keeping me between a TSH of 4 and 5.5, still in the
"normal" range, despite the fact that I still have the full range of hypothyroid
symptomsfatigue, weight gain, irregular menstrual periods, dry skin, hair falling
outat those levels.
3. Thyroid Health Information Site: "The Underdiagnosed Epidemic" by Ward Dean, M.D.
Click here (Dean) and go to "The Underdiagnosed Epidemic" for the full text.
Although many people exhibit symptoms of hypothyroidism, they usually don’t
receive treatment for this condition if they have normal blood test readings. Their
physicians often tell them that their symptoms are due to other causes or that
their problem is "all in their head." I have known many patients who were referred
to psychiatrists to treat their so-called "psychosomatic" problems. However, when they were later given thyroid replacement therapy, they improved dramatically.
4. A long compilation of patients’ descriptions of where they need their TSH levels to be for
them to feel well
Click here (TSH Experiences) for longer texts.
Nancy N: I start to get hypo symptoms when my TSH starts moving up towards 1.0. I feel best and have no hyper symptoms when my TSH is at about 0.13 or less.
Paula: I had hypothyroid symptoms at a TSH of 1.8, last spring, and for years
before - my TSH tests were always "normal" - but apparently that is not normal for *me*. I had a TRH stimulation test which was resoundingly positive for
hypothyroidism, when my baseline TSH was only 2.4 to 2.8.
CW: If my TSH gets above 2.0, I get all kinds of bizarre infections I do NOT get
Marie: My latest TSH was 0.1 (under normal range) but my doctor still agreed to a
trial increase in thyroxine as I was still very symptomatic and my Free T4 and Free
T3 blood tests were low down in the normal range….I am feeling a lot better now.
LuvARabbit: …my old dr., he didn't want to treat me because my tsh was 3.3 and
he totally ignored my symptoms and told me to see a shrink. Funny, with a new
doc and Armour thyroid, I'm doing so much better….
1. Living Well With Hypothyroidism: What Your Doctors Don't Tell You...That You Need to
Know by Mary J. Shomon, author of About.com Guide to Thyroid Disease, Harper Collins Publishers, New York, 2000
The current TSH levels used by laboratories to define the "normal" range of thyroid function and the use of the TSH test as a primary means of diagnosis need to be significantly reevaluated. The .5 to 5.5. "normal" range for thyroid function does not give 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 at the lower
end. (p. 252)
2. The Thyroid Solution by Dr. Ridha Arem, Ballantine Books, New York, 1999
Increasingly, more and more physicians believe that you can be suffering from
hypothyroidism even though your blood tests, including TSH, are normal. (p. 223)
To achieve a good balance, you need to have your TSH maintained between 0.5
and 2.0 milli-international units per liter while receiving thyroid hormone
treatment. A TSH ranging between 2.0 and 4.5 may mean some thyroid hormone
deficiency.…Often all it takes to restore normal thyroid status is a small increase in
the dose, which might have significant effects on the way you feel. (p. 248)
since July 29, 2001.