2 Solid reasons why we don't trust just TSH

[HRTstudent]

I see this come up a bit: "Is my thyroid fine? My TSH is X.XX"

Then we must say, unfortunately, the TSH has been built up "the" thyroid diagnostic criteria, but in reality, it falls short much of the time. It might be good enough for the endo (who thinks 200 total T is perfectly normal for a young man), but it's not sufficient if you're actually interested in optimal health.

Please, take the time to read this brief tidbit from Dr. Mariano from 2010:


http://www.definitivemind.com/2010/07/24/the-usefulness-of-tsh/

The Usefulness of TSH

I prefer monitoring actual thyroid hormone levels in addition to TSH (Thyroid Stimulating Hormone) for assessment and treatment, rather than relying on TSH alone.

One major factor is that there are two separate compartments for thyroid hormone: The brain compartment and the body compartment. These are separated by the blood brain barrier. Thyroid hormone cannot pass through the blood brain barrier without active transport. This is controlled by astroglial metabolism and signaling.

The astroglia are non-electrical signaling, mobile brain cells which, among their numerous functions, maintain the integrity of the blood brain barrier, maintain brain metabolic activity, control neuron growth, control synaptic connections and signaling activity, network neurons and other glial cells, and participate in information processing. They are the most numerous cells in the brain. They also are the brain cells that convert T4 to T3. A large number of astroglial cells are also the stem cells of the brain (approximately 55 billion of them). The number of neuroglial cells determines one’s intelligence. Einstein’s cerebral cortex, for example, had twice as many neuroglial cells than normal. He had about the same number of neurons as a normal person.

TSH is a brain signal to the pituitary gland that more thyroid hormone needs to be produced. Given that TSH is made by the brain, TSH actually represents the brain’s need for thyroid hormone since the brain is in a different compartment than the body.

TSH production depends significantly on brain health / mental health. If one has metabolic problems, for example (and mental illnesses often have metabolic problems as part of their pathophysiology), then the brain may not be capable of either measuring thyroid hormone signaling adequately or may not be capable of producing adequate TSH. Thus, TSH may be low relative to the actual blood levels of Thyroid Hormone (T4, T3, Free T4, and Free T3). In this case, TSH can be low and blood thyroid levels can be low. Such a person will be physiologically hypothyroid yet TSH falsely indicates adequate or high thyroid levels.

Given the two thyroid compartments, another problem may arise: If the body’s activation of thyroid hormone (T4 to T3 conversion) is greater than the brain’s activation of thyroid hormone or if active transport of thyroid hormone across the blood brain barrier is impaired (such as in conditions where ATP production is slowed), then one can have high Free T3 (representing active thyroid hormone) yet also high TSH. The body may be in a state of hyperthyroidism (there are only T3 receptors and no T4 receptors) yet the brain is hypothyroid.

The above are examples of non-thyroid illnesses – where the may be nothing wrong with the thyroid gland yet thyroid signaling is affected.

Thyroid hormone levels in the brain and in the body can be very different. This has been shown in studies measuring blood thyroid hormone levels and Cerebrospinal Fluid thyroid levels. This can lead to misinterpretations of thyroid function – particularly when it comes to brain and body function. This is why I prefer to monitor actual thyroid hormone levels (Total T4, Free T3 at least, and Total T3, Free T4) and TSH to help get the bigger picture of thyroid signaling activity and thus function. Since thyroid signaling is also affected by other factors (e.g. nervous system, endocrine system, immune system function, metabolism and nutritional status), these other factors may be also highly important to assess how a certain thyroid signaling state was created.




Hope this helps some of you who are trying to tackle sub-par thyroid issues! Feel free to share noteworthy thyroid articles as well .

[asiandudexxx]

Wow really good info, thanks! I always assumed metabolism was constant throughout the whole body, I didn't realize the brain and body could have different metabolic states.

If one has low TSH and low blood levels of FT3/FT4, could that represent the fact that the brain is "satiated" although the body may not be?

Hopefully one day there will be measurement of T3 receptor activity vs. levels pooled in the blood so we can get a more accurate picture of metabolic activity.

[supernatural28]

My TSH is normal. But I'm definitely doing a full thyroid panel soon..

[asiandudexxx]

My TSH is normal. But I'm definitely doing a full thyroid panel soon..

Do you have any hyper/hypo symptoms?

The hardest part is convincing your gp to test more than tsh. Took me 3 years ..

[junk2222yard]

In the same vein as HRT's post:

Talk to any Endocrinologist or most medical-school-trained doctors, and you will be told that:

1. The TSH lab is a reliable physiological marker of thyroid function (i.e. whether you are hypo or hyper)
2. It’s an accurate guide for your medication supplementation amount.
3. The lower your TSH while on desiccated thyroid, the greater your chance of osteoporosis or heart attack.
4. There’s an optimal place to be on the TSH range when on meds, such as between 1 and 2, or ‘fill-in-the-blank’.

But, experiences of patients have found ALL THE ABOVE to be totally false!

Not only are patients with OBVIOUS hypothyroid symptoms being told they have no thyroid problem because of a “normal” TSH (i.e. a TSH number in range), they are being held hostage to the TSH range when on thyroid medications, EVEN THOUGH the patient continues to have typical hypothyroid symptoms while in the range...

Excerpted from http://www.stopthethyroidmadness.com...y-its-useless/

[steroid.com 1]

Hey HRT, I just saw your HRT Specialist title...I may have missed it before and for that I apologize.

Congrats man, you've earned it!

Keep up the good work man, you're a true asset to the board

[HRTstudent]

Hey HRT, I just saw your HRT Specialist title...I may have missed it before and for that I apologize.

Congrats man, you've earned it!

Keep up the good work man, you're a true asset to the board

Thanks for the compliment gdevine. I didn't notice either lol.

[junk2222yard]

This is a very good explanation of why not to use TSH, and why to go by Free T3, Free T4 and symptoms! (Click link below to read full article.)

Optimum Diagnosis and Treatment of Hypothyroidism With Free T3 and Free T4 Levels

The big myth that persists regarding thyroid diagnosis is that an elevated TSH level is always required before a diagnosis of hypothyroidism can be made. Normally, the pituitary gland will secrete TSH in response to a low thyroid hormone level. Thus an elevated TSH level would typically suggest an underactive thyroid.

The traditional tests of thyroid function, the T4 (or total T4), T3-uptake, FTI, 'T7', total T3, and T3-by-RIA tests should be abandoned because they are unreliable as gauges of thyroid function. The most common traditional way to diagnose hypothyroidism is with a TSH that is elevated beyond the normal reference range. For most labs, this is about 4.0 to 4.5. This is thought to reflect the pituitary's sensing of inadequate thyroid hormone levels in the blood which would be consistent with hypothyroidism. There is no question that this will diagnose hypothyroidism, but it is far too insensitive a measure, and the vast majority of patients who have hypothyroidism will be missed...

Excerpted from http://www.mercola.com/article/hypot...nosis_comp.htm

[VTX1800]

Interesting...good read

[junk2222yard]

Yet more on the topic:

Hypothyroidism is one of the most misdiagnosed, under-diagnosed or ignored health conditions. Most traditional information taught in medical schools about thyroid testing is inaccurate or incomplete. Ordinarily, a single blood lab test is ordered — the TSH level (Thyroid Stimulating Hormone). This hormone is made by the pituitary gland to stimulate the thyroid to produce thyroid hormones. In a healthy-working thyroid gland, there is a biochemical feedback loop that slacks off on the production of TSH if there are enough thyroid hormones present. Doctors mistakenly think that if the TSH is normal the thyroid is normal. This is too simple and not valid. This test needs to be looked at, but not without others.

Excerpted from http://www.awarenessmag.com/janfeb5/jf5_thyroid.html

She touches on an analysis of all of the possible tests, body temps and importance of *symptoms*, synthetic Thyroid drugs versus Natural Dessicated Thyroid, and more. Very good write-up.

[Trific]

I just came across some thyroid & adrenal info myself:

http://www.drrind.com/therapies/thyroid-scale-matrix