Dr. Valerie Nelson​

Board Certified Natural Integrative Doctor

Why Thyroid Blood Work is Not the Best Diagnostic Tool

Under-Active thyroid continues to be a growing epidemic. 27 million Americans are suspected to have the disease, yet only about 10 million have actually been diagnosed.

Many doctors rely solely on TSH testing for diagnosing and in some cases, T4 or throxine hormones. Unfortunately, there is not one single isolated blood test that can accurately diagnose an under active thyroid.

 TSH (thyroid stimulating hormone) is made by your pituitary gland in the brain. So, TSH is not a thyroid hormone, it is actually a pituitary hormone. The pituitary gland produces TSH to tell the thyroid to produce thyroid hormone. But before your thyroid gets this signal, it has to wait for the pituitary to send the signal. Many doctors assume that the pituitary gland is working properly. Sometimes, it is not!

In essence, you can have all of the symptoms of a thyroid problem and your thyroid may be working fine, but the pituitary may be causing the trouble.

For the pituitary to function properly, it must first get a signal from the hypothalamus gland, which is located in the brain to produce a hormone called TRH (thyrotropin releasing hormone). This whole process actually begins with the hypothalamus gland.

When the thyroid hormone levels in the blood go down, TSH should go up signaling for the thyroid to release more hormone. When thyroid hormone in the blood rises to the proper amounts, the hypothalamus will shut the signal off to the pituitary gland, normalizing TSH or lowering it. 

Now, understanding what TSH is, it is important to understand that the thyroid is composed of about 90% T4 and 10% T3. T3 is 5 times more active than T4 and T3 is the hormone that makes your body run efficiently.

 To make adequate amounts of T3, the body must first have the ability to convert T4 into T3. The liver and the intestines play a big role in this conversion process. Many individuals are having difficulty with this conversion process. Some conditions that prohibit this conversion process are inflammation, stress, blood sugar issues, fibromyalgia, PMS, and depression. Imbalances in intestinal gut bacteria can also interfere with this conversion, leading to inadequate levels of T3 inside the body.

If you have any of these conditions, your body has the tendency to convert T4 into Reverse T3. Reverse T3 or rT3 will block thyroid hormones from getting into the cells. This presents a big problem.

 This means that your lab results may very well show normal levels of TSH, T4 and T3, but you can still have all of the symptoms of under-active thyroid because the T3 is not making it into your cells. Most lab work just refers to the amount of hormone in the blood, but not inside the tissues or cells. To feel good, you need to have adequate levels of T3 inside of your cells. However, no one test can determine this. This is why we rely so heavily on symptoms testing to determine whether you have an under-active thyroid.

This can be very frustrating for a patient because they are only being treated based on blood work and not on how the patient actually feels. Many of these patients are being put on psych meds because the doctors believe that their symptoms are ‘all in their heads’!

In addition to that, most doctors will prescribe synthetic T4 or Synthroid. But if your body cannot convert T4 into T3, then you are never going to feel better. Your blood work will look like everything is okay, but in fact, it is not. It really does not do a lot of good to prescribe a synthetic that only contains T4.

 Patients are frustrated because they tell their doctors that they do not feel well, but the patients are told that their blood work is just fine.

Again, we work with natural thyroid which contains both T4 and T3. We teach our clients how to identify if under-active thyroid is the cause of their ill feeling. We teach them how to determine how much natural thyroid that they need. It typically take about 2 – 3 weeks to determine the optimal dose for their system.

These are some comments from medical doctor, Barry Durrant-Peatfield’s book, Your Thyroid and How to Keep it Healthy.

“Most physicians fall back on the blood test to adjust doses, but I think it is tiresome to have repeated tests, when the patient – who after all, knows how they feel better than anybody – many patients often have a much better idea of their requirements than any blood test. I have always taught my patients to check their pulse rate once or twice a day and their resting temperature and to make an overall assessment as to whether they feel well or not."

Since 1898 doctors have been diagnosing hypothyroidism, but in the last three – four decades, medical dogma has come to say, ‘you cannot and must not make the diagnosis without the blood test.’ There have been about 40 different tests for thyroid illness because NOT ONE has been found to be reliable.

I have seen patients who have had several successive blood tests because the doctor very properly suspected a thyroid problem, but could find no abnormality until perhaps the 4th or 5th test, by which time the patient has had worsening symptoms for further months or years. Only then, and all too late, does the doctor feel justified in treating the patient whose life has by now been irrevocably changed by depression, chronic ill-health, perhaps loss of job and destruction of relationships. I have seen patients whose hypothyroidism is so severe that they actually have myxoedema, but they are treated for fluid retention with diuretics; for depression and exhaustion with antidepressants, for constipation with opening medications, and excess weight by rigorous dieting. All the time the diagnosis could have made by just looking and listening to the patient.”

Dr. Durrant-Peatfield also notes that one example of the blood tests concerning TSH is that normal levels are quoted as around 0.15 micro units as the lower level, and anything from 3.5 – 6.0 micro units as the upper number. These figures are crucial, since if you are within this range, you will be told that you are normal – whatever the symptoms. Almost as bad is to be told that you are ‘borderline’ and come back in 6 months. As a result of this test, thousands are denied treatment. The American Association of Clincal Endocrinologist quote .3 – 3.0 as the optimal range to aim for. In fact, a level of 2 micro units per milliliter should arouse suspicion, and anything over 2.5 should be diagnostic.

Keep in mind that we have seen many cases where the blood work is completely normal, even to these standards, but the amount of thyroid hormone that is in the tissues is not being measured by the blood work. 

Again, when we work with individuals who come in for an evaluation, we have them closely monitor and chart out certain body functions, as well as doing a manual test of symptoms. We have them come back in a few weeks and review how the whole process went, as well as reviewing their charts to ensure that they are on the proper dose. 

It takes anywhere from just a few days up to several weeks to determine the proper dose for each individual, but the process is well worth it, especially for those who have been plagued with symptoms for quite some time without any explanation.

Because you are nourishing your whole glandular system, it is very important to stay on the supplement program that was put together for you during your initial exam with Dr. Nelson to have the best overall results.

 Dr. Valerie Nelson,

Natural Doctor, Board Certified Integrative Medicine

Resources for this article were provided in part by Your Thyroid and how to keep it healthy and TSH Report by Dr. Devein Dobrzynski, DN

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