Overview

Many people feel like they have symptoms of hypothyroidism, but have been told that their "thyroid test is normal." This is an unfortunate consequence of the current standard of care in allopathic (conventional) medicine, which relies solely on testing the hormone called Thyroid Stimulating Hormone (TSH) in order to reduce costs. If you go to an allopathic (conventional) medicine doctor (an MD or DO) or a nurse practitioner, you will likely only get the TSH test, because insurance companies tend to consider additional testing unnecessary, and may punish doctors who order additional tests with charges of "fraud, waste, and abuse."

In reality, there are many additional tests that are relevant to the diagnosis and treatment of thyroid disorders that Dr. Weyrich considers as part of his naturopathic functional medicine practice. Not all are necessary for all patients, but all need to be considered. Dr. Weyrich describes theory behind the tests in his essay on the Thyroid System Control.

Discussion on this web page is broken down according to the disorder being tested: hypothyroidism, hyperthyroidism, or both.

Tests for both Hyperthyroidism and Hypothyroidism

Basal Body Temperature

Normal axillary temperature is 97.8 to 98.2 degrees Fahrenheit. Normal rectal temperature is 98.6 to 99.2 degrees Fahrenheit. Oral temperatures may be elevated above axillary temperatures by chronic sinusitis and hence are less reliable measures of basal body temperature. Menstruating women should measure their basal body temperature the second and third mornings after 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, nor excitement in the preceding 12 hour period. Electric blankets, heated water beds, excessive layers of bed-clothes, etc. may falsely elevate basal body temperature measurements. Use a reliable thermometer and place snuggly in the arm-pit 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 along with other symptoms of hypothyroidism.

Complete Blood Count with Differential

This standard lab test is part of a routine annual physical. You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months. Dr. Weyrich is particularly interested in the markers for anemia (RBC, Hct, MCV, RDW), but anything that is out of range requires investigation.

Comprehensive Metabolic Panel

This standard lab test is part of a routine annual physical. You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months. Dr. Weyrich is particularly interested in the markers for liver health (AST, ALT, albumin), but anything that is out of range requires investigation.

TSH

This is the standard test used by conventional (allopathic) doctors (MD, DO) to diagnose thyroid problems. As discussed in Thyroid System Control, TSH is an indicator of hypothalamic and pituitary function, and represents a key control signal in keeping the thyroid system in proper balance.

You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that total T4 be done at the same time (and also total T3, free T3, and reverse T3 if hypothyroidism is being evaluated).

Total T4

This is the standard test used by conventional (allopathic) doctors (MD, DO) to diagnose hyperthyroid problems. As discussed in Thyroid System Control, total T4 is an indicator of the response of the thyroid gland to stimulation by TSH.

You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that total TSH be done at the same time (and also total T3, free T3, and reverse T3 if hypothyroidism is being evaluated).

Thyroid Peroxidase (TPO) and Thyroglobulin (TGAb) Antibodies

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 auto-immune disease Hashimoto's thyroiditis.

An old 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 thyroid status, then the tests need to be done.

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

Thyroid Ultrasound

The routine use of this test is somewhat controversial. The American Academy of Family Physicians considers this test to be unnecessary unless there is suspicion of an enlarged or lumpy thyroid gland (which could indicate thyroid cancer). See also this PubMed article.

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 that is 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 staus 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, in order to facilitate detection of changes.

Thyroid Scan

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. 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."

In cases where Dr. Weyrich suspects these issues, he refers the patient to an endocrinologist to do the testing and evaluation.

Thyroid Fine Needle Biopsy

This test is indicated to rule out thyroid cancer when an ultrasound exam shows suspicion thyroid nodules.

In cases where Dr. Weyrich suspects these issues, he refers the patient to an endocrinologist to do the testing and evaluation.

Optional Thyroid Releasing Hormone (TRH) and MRI

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

Additional Tests for Hypothyroidism Only

Total T3

As discussed in Thyroid System Control, comparison of total T3 to total T4 is an indicator of the conversion of T4 to T3 in the peripheral tissues.

You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that total T4 be done at the same time (and also TSH, free T3, and reverse T3).

Free T3 (fT3)

As discussed in Thyroid System Control, free T3 represents the amount of T3 that is actually available to the cells to promote energy production. In addition, comparison of total T3 to free T3 gives an indication of the degree of protein binding of T3.

You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that total T3 be done at the same time (and also TSH, total T4, total T3, and reverse T3).

Reverse T3 (rT3)

As discussed in Thyroid System Control, reverse T3 acts to reduce production of TSH and reduces cellular energy production. This test is important for teasing out the cause of difficult-to-treat cases.

You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that total T3 be done at the same time (and also TSH, total T4, total T3, and free T3).

Adrenal Stress Test

As discussed in Thyroid System Control, conversion of T4 to T3 is controlled in part by adrenal cortical production of cortisol.

The adrenal cortex produces a number of steroid hormones, including cortisol, which has been dubbed the "stress hormone." The thyroid control system senses cortisol and stress levels, and makes adjustments to 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 4 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. Dr. Weyrich keeps both test kits in stock; the patient takes the kit home, collects the specimens, and mails the specimens directly to the lab, along with payment.

Optional Free T4 (fT4)

As discussed in Thyroid System Control, comparison of total T4 to free T4 gives an indication of the degree of protein binding of T4. This comparison should give the same conclusion as comparing total T3 to free T3, but may be useful as a cross-check in cases where "things don't add up." You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that total T4 be done at the same time.

Optional Thyroxine-Binding Globulin (TBG)

As discussed in Thyroid System Control, thyroxine-binding globulin binds to both T3 and T4, reducing the amount that is free. This test is most useful when comparison of total T3 to free T3 (or T4 to fT4) indicates an abnormal proportion of bound T3 (or T4). You can use a test that is up to 6 months old if there has been no change in your health status, diet, or medications in the past 6 months, but proper interpretation requires that CMP be done at the same time.

Optional Sex Hormone Binding Globulin (SHBG), Estrogen, and Testosterone

The thyroid system interacts with the gonadal system (both are controlled in part by the pituitary). Imbalances in one system can affect the other system. In particular, levels of sex hormone binding globulin (SHBG) are sensitive to the level of T3 as well as the levels of estrogen and testosterone. Low levels of SHBG despite normal levels of estrogen or testosterone suggest low effective levels of circulating T3. Therefore, in some cases Dr. Weyrich will recommend testing SHBG and estradiol for women, or SHBG, free testosterone, and total testosterone for men.

Optional Serum Iron, Ferritin, and Total Iron Binding Capacity (TIBC)

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.

Optional Iodine Nutritional Status Testing

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 lacks scientific rigor, and is difficult 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 useful.

This test would be used only in the case that iodine deficiency were suspected, in order to prevent overcompensating by supplementing with too much iodine, which can be toxic. The test should be repeated every 6 months while supplementing with iodine.

The test kit for the iodine loading test must be purchased (and special ordered) in advance from Dr. Weyrich.

Optional Heavy Metal Toxicity Testing

As discussed on the web page how the thyroid system works, 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 not reliable for detecting all forms of mercury in the body, but does have the advantage of being relatively inexpensive and easier and is useful as a screening test.

Additional Tests for Hyperthyroidism Only

Thyroid Stimulating Immunoglobulin (TSI) and Thyroid Stimulating Hormone Receptor Antibody (TRAb)

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 the auto-immune Grave's Disease.

An old positive test is sufficient to establish the presence of Graves' Disease, regardless how old the test is. However, if previous testing was negative or there has been a change in your thyroid status, then the tests need to be done.

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

Optional 24-hour Catecholamines Test

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.

Ophthalmologic Exam

In the case that Dr. Weyrich suspects exophthalmos (eye involvement due to Graves' Disease), he will make a referral to an ophthalmologist for further evaluation.

Additional Tests for Auto-Immune Thyroid Problems

If the above tests suggest possible Hashimoto's or Graves' disease, then certain non-conventional tests may indicate non-conventional treatments that may be very beneficial. These include:

Spinal Evaluation

Hippocrates, the "father of modern medicine", said "first look to the spine" for the cause of disease. In some cases, treatable problems with the spine can reduce blood flow to the brain and nerves of the autonomic nervous system that regulate the function of the thyroid, adrenal, and digestive systems. For additional information regarding evaluation of the spine, please contact Dr. Robert Gear, Jr.

References