Thyroid Disease Diagnosis

The normal axillary (armpit) temperature is 97.8 to 98.2 degrees Fahrenheit. The normal Normal rectal temperature is 98.6 to 99.2 degrees Fahrenheit. Chronic sinusitis may elevate oral temperatures above axillary temperatures and hence is a less reliable measure of basal body temperature. Menstruating women should measure their basal body temperature the second or third morning after the onset of menstrual flow. The basal temperature should be taken after a good night's rest before arising in the morning, with no food, exercise, or excitement in the preceding 12-hour period. Electric blankets, heated water beds, excessive layers of bedclothes, etc., may falsely elevate basal body temperature measurements. Use a reliable thermometer and place it snuggly in your armpit for 10 minutes before reading [Starr2005, pg 17]. Note that in cases of chronic inflammation, a basal body temperature above 98.2 F may be observed despite other symptoms of hypothyroidism.

As a general rule, Dr. Weyrich can use your previous blood tests without ordering new tests, if:

• Your previous test is less than 6 months old;
• There has been no change in your health status, symptoms, diet, or medications since your previous test was done;
• The previous test was not abnormal;
• All the relevant thyroid function tests (TSH, T4 free T4, T3, free T3, reverse T3, and Thyroid Binding Globulin) were done at the same time.

Dr. Weyrich will evaluate these criteria on a case-by-case basis.

This standard lab test is part of a routine annual physical. Dr. Weyrich is particularly interested in the markers for anemia (RBC, Hct, MCV, RDW), but anything out of range requires investigation.

This standard lab test is part of a routine annual physical. Dr. Weyrich is particularly interested in the markers for liver health (AST, ALT, albumin), but anything that is out of range requires investigation.

TSH is the standard test conventional (allopathic) doctors use to diagnose thyroid problems. As discussed in Thyroid System Control, TSH is a marker of hypothalamic and pituitary function and is a key control signal in keeping the thyroid system in proper balance.

Total T4 is the standard test conventional (allopathic) doctors use to diagnose hyperthyroid problems. As discussed in Thyroid System Control, total T4 indicates the thyroid gland's response to stimulation by TSH.

If the TSH and T4 tests indicate either a hypothyroid or hyperthyroid condition, then tests for thyroid peroxidase (TPO) and thyroglobulin (TGAb) antibodies should be done to confirm or rule out the autoimmune disease Hashimoto's thyroiditis.

A previous positive test is sufficient to establish the presence of Hashimoto's thyroiditis, regardless how old the test is. However, if previous testing was negative or there has been a change in your health status, then the test may need to be redone.

Repeat testing (at 6-month intervals) is generally only indicated if Naturopathic treatments are used to reduce or eliminate the autoimmune triggers. Successful Naturopathic treatment should show a decreasing trend of the antibody titers.

The routine use of the thyroid ultrasound test is controversial. The American Academy of Family Physicians considers it unnecessary unless there is suspicion of an enlarged or lumpy thyroid gland (which could indicate thyroid cancer). See also [Nou2014  🕮 ].

Dr. Weyrich prefers to err on the side of safety and obtain a baseline test for all patients with abnormal thyroid function, symptoms suggesting an enlarged thyroid gland or a positive physical exam for thyroid gland abnormalities. You can use a test up to 3 years old if the test results were normal and there has been no change in your thyroid status in the past 3 years. If previous test results were abnormal or your thyroid status has changed, then you need a test within the past 6 to 18 months, depending on the degree of abnormality.

It is best to use the same laboratory for repeat tests to facilitate the detection of changes.

This test is indicated to rule out thyroid cancer as a cause for hyperthyroid symptoms or thyroid nodules. According to the Australian Family Physician,

"Thyroid scans are functional tests that assess the activity of the thyroid ... Early thyroid scans were done with radioactive iodine, but this has largely been replaced by technetium (Tc-99m) pertechnetate, which sufficiently mimics the behavior of iodine, involves a much lower radiation dose and costs considerably less. Iodine scans are now only used for specific situations in cases of proven thyroid cancer."

When Dr. Weyrich suspects these issues, he refers the patient to an endocrinologist for testing and evaluation.

A thyroid fine needle biopsy is indicated to rule out thyroid cancer when an ultrasound exam reveals suspicious thyroid nodules.

When Dr. Weyrich suspects these issues, he refers the patient to an endocrinologist for testing and evaluation.

In cases where Dr. Weyrich suspects problems with the Hypothalamus or Pituitary, he refers the patient to a neuroendocrinologist for testing and evaluation.

As discussed in Thyroid System Control, comparing total T3 to total T4 indicates the effectiveness of converting T4 to T3 in the peripheral tissues.

Testing of total T3 by the LC-MSMS method appears to be more reliable than by the immunoassay method. Not only did TSH correlate better with total T3 measured by LC-MSMS than with immunoassay, but LC-MSMS values were lower than immunoassay values [Masika2016  🕮 ]. Dr. Weyrich speculates that these findings may be due to binding protein abmormalities interfering with immunoassay values, and probably are also true for other types of thyroid tests, such as total and free T4, as well as free and reverse T3.

As discussed in Thyroid System Control, free T3 represents the amount of T3 that is actually available to the cells to promote energy production. Comparing total T3 to free T3 suggests the degree of T3's protein binding.

As discussed in Thyroid System Control, this test helps determine the cause of difficult-to-treat cases.

Note that reverse T3 is a specialty test that may have a relatively long laboratory turn-around time.

As discussed in Thyroid System Control, adrenal cortical cortisol production partially controls the conversion of T4 to T3.

The adrenal cortex produces several steroid hormones, including cortisol, which has been dubbed the "stress hormone." The thyroid control system senses cortisol and stress levels and adjusts TSH production and T4 conversion to T3/rT3 accordingly.

The best way to evaluate the functional status of the adrenal cortex is by using specialty testing (i.e., not offered by conventional labs) that requires collecting samples of either saliva or urine at four different times of day and night (upon waking, noon, late afternoon, and bedtime) [blood samples could also be used if the patient is in a 24-hour care facility, but this is impractical for outpatients]. Dr. Weyrich prefers the dried urine test from Precision Analytical but also uses the saliva test from DiagnosTechs. Alternatively, a cortisol blood test drawn at the same time as thyroid functional tests can be helpful.

As discussed in Thyroid System Control, comparing total T4 to free T4 indicates the degree of protein binding of T4. This comparison should give the same conclusion as comparing total T3 to free T3 but may be helpful as a cross-check in cases where "things don't add up."

As discussed in Thyroid System Control, thyroxine-binding globulin binds to T3 and T4, reducing the free amount of each. This test is most useful when comparing total T3 to free T3 (or T4 to free T4) and evaluates an abnormal proportion of bound T3 (or T4). Proper interpretation requires that collection of CMP and SHBG be done simultaneously.

The thyroid system interacts with the gonadal system because the pituitary partly controls both. Imbalances in one system can affect the other. In particular, levels of SHBG are sensitive to the levels of T3, estrogen, and testosterone. Low levels of SHBG despite normal levels of estrogen or testosterone suggest low levels of circulating free T3. Therefore, in some cases, Dr. Weyrich will recommend testing SHBG and estradiol for women or SHBG, free testosterone, and total testosterone for men.

An important differential diagnosis for complaints of low energy is iron deficient anemia. Therefore, a complete work-up of suspected iron deficiency is also appropriate.

Unfortunately, there is no good laboratory test for low iodine status. Measuring how long it takes for the skin to absorb tincture of iodine has been used (quick absorption indicates the body is "hungry for iodine"), but it lacks scientific rigor and is challenging to apply to patients with darker skin.

Another test that is sometimes used is an iodine loading test, in which the patient takes a measured amount of iodine and then collects the next 24 hours of urine produced, which is sent to a laboratory to measure how much of the oral dose of iodine was retained (if more than 10% is retained, then the body was "hungry for iodine"). This test also lacks sufficient scientific rigor, but can be helpful.

This test would be used only if iodine deficiency were suspected to avoid overcompensating with too much iodine, which can be toxic. The test should be repeated every six months while supplementing with iodine.

As discussed in Thyroid System Control, mercury intoxication reduces T4 conversion to T3, and increases the conversion to rT3. Testing for the presence of mercury toxicity is best done using a urine provocation test, in which the patient takes the oral medication DMSA (meso-2,3-Dimercaptosuccinic acid, AKA Captomer or Succimer), which chelates mercury in the body and pulls it into the urine, and then collects a 24-hour urine sample which is then analyzed for the presence of elevated mercury (and other heavy metals).

The use of hair for heavy metal testing is unreliable for detecting all forms of mercury in the body. Still, it is relatively inexpensive, more straightforward, and helpful as a screening test.

If the TSH and T4 tests indicate a hyperthyroid condition, then tests for Thyroid-Stimulating Immunoglobulin (TSI) and Thyroid-Stimulating Hormone Receptor Antibody (TRAb) should be done to confirm or rule out autoimmune Grave's Disease.

A previous positive test is sufficient to establish a diagnosis of Graves' Disease. However, the test must be redone if the previous testing was negative but signs and symptoms suggest Graves' diease.

Repeat testing (at 6-month intervals) is generally only indicated if Naturopathic treatments are being done to reduce or eliminate the autoimmune triggers. Successful Naturopathic treatment should show a decreasing trend of the antibody titers.

If a patient shows signs of hyperthyroidism but TSH and T4 levels do not support a diagnosis of hyperthyroidism, then the possibility of excessive production of catecholamines (e.g., adrenaline) by the adrenal medulla or an ectopic tumor must be considered.

If Dr. Weyrich suspects exophthalmos (eye involvement due to Graves' Disease), he will refer the patient to an ophthalmologist for further evaluation.