Articles by Dr. Erdman are for informational purposes, and are not to be taken as specific medical advice.
Now that we’ve covered the anatomy of the thyroid, the
possible disruptors of thyroid function and the multitude of symptoms a
dysfunctional thyroid can produce in the past three articles, we are now ready
to review the testing necessary to diagnose a low functioning thyroid.
The traditional diagnosis of thyroid function is done by
assessing how much thyroid stimulating hormone (TSH) the pituitary gland
produces. This is kind of an indirect measure of thyroid function. Normal
levels should be between 1.0 – 1.5 milli-international units per milliliter. As
the name thyroid stimulating hormone suggests, the pituitary gland produces
more TSH in response to low thyroid function. This action stimulates the
thyroid to produce more thyroid hormone. Hence the higher the TSH production,
the more likely you are to have hypothyroidism. However, while this is the
primary test, it simply may not be adequate enough in many cases.
It is well known that many patients where the TSH levels
fall within the normal ranges, still exhibit signs and symptoms of low thyroid.
The TSH test frequently misrepresents the relationship between the pituitary
and the thyroid. Part of the problem is that the TSH test fails to account for
endocrine disrupting chemicals, which affect many endocrine functions, not just
the thyroid. Because some chemicals disrupt other hormones along the signaling
system, it can be difficult to identify an imbalance with the TSH test alone.
To see a better picture of your thyroid health, the
following lab tests can also be assessed:
Free T3 and T4: these are the actual thyroid hormones. T3
has three iodine molecules attached, and T4 has four. T3 is the biologically
active form used by the body. Normal T4 is between 0.9 ng/dL, and T3 is between
240 -450 pg/dL.
Thyroid antibody testing is done by performing two tests,
the thyroid peroxidase and antithyroglobulin antibody tests. These two measures
will tell you whether you have an autoimmune problem, which means your immune
system is attacking its own thyroid. Most doctors rarely give this test a
thought. But it is important to rule out this mode of dysfunction.
Use basal body temperatures as another form of testing. If
your morning body temperature is below 97.6* F on a regular basis, this is a
positive sign of low thyroid function.
In cases where TSH is normal, yet symptoms persist, a
thyrotropin releasing hormone (TRH) stimulation test may be performed. This
test involves getting a shot of thyrotropin (produced by the hypothalamus
gland), which causes the pituitary gland to empty itself of all its stored TSH
into the blood stream. Depending on how high these levels rise to can mean a
dysfunctional pituitary gland.
A reverse T3 (RT3) test can be performed when chemical
toxicity is suspected. Reverse T3 is metabolically inactive and elevated levels
indicate heavy metal toxicity is affecting the thyroid function. High stress
can also cause RT3 to be elevated, as can adrenal fatigue, low iron stores
(ferritin) and acute or chronic illness.
As you can see,
diagnosing thyroid conditions is complex. I am no expert in this field, and if
I needed help with a problem like this, I would seek out a natural minded
holistic endocrinologist. In our area, I have no idea if one even exists. I
have patients that travel to the Altoona area for this type of holistic
treatment from medical personnel.
In the next and final article on the thyroid, we will look
at the treatments available to those with low thyroid function.