Twenty million Americans are affected by hypothyroidism. Laboratory testing needed for the proper diagnosis and treatment of hypothyroidism can be overwhelming and confusing at times. This, in large part, is due to the number of testing and markers available. Despite this, testing is necessary to ensure the proper treatment and rectification of patient symptoms. This article will focus on what tests should be done bi-annually for hypothyroid patients to keep them as healthy as possible.
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What is Hypothyroidism?
Hypothyroidism is a disease affecting the thyroid gland, which is a butterfly-shaped organ that sits in the neck. The thyroid gland makes thyroid hormones, primarily triiodothyronine (T3) and thyroxine (T4). The thyroid hormones are used by every single cell in the body and affect body temperature and body temperature regulation, sex hormones, hair and nail growth, energy levels, gastrointestinal functioning, cognitive functioning, and more. The thyroid gland and, thus production of these hormones is controlled by the Hypothalamic Pituitary Thyroid (HPT) axis. When the hypothalamus, which is a center in our brain, senses our body needs more thyroid hormone, it will release a hormone called thyroid releasing hormone (TRH) to the pituitary gland. In response, the pituitary gland releases thyroid stimulating hormone (TSH) to the thyroid gland. The thyroid gland should respond by releasing thyroid hormones T4 and T3. Most of what the thyroid makes is T4. However, the more active thyroid hormone is T3. T4 gets converted into T3 in the peripheral tissues, including the liver and the kidneys. The amount of circulating T4 and T3 is sensed by the hypothalamus, which will release TRH dependent upon these levels; this is called a feedback loop. When thyroid hormone levels are low, or if the body is in greater need, the hypothalamus releases more TRH. Conversely, when thyroid hormone levels are high or when the body is not in need of thyroid hormones, the release of TRH is reduced. However, in hypothyroidism, the thyroid hypo-functions, meaning it does not respond to TSH stimulation, and thus, levels of thyroid hormones are low.
What Causes Hypothyroidism?
The primary cause of hypothyroidism is the autoimmune condition Hashimoto's thyroiditis. In Hashimotos, immune cells attack the thyroid gland, causing inflammation and destruction of the cells of the thyroid, and thus a lack of response to TSH. Additional causes of hypothyroidism include surgical removal of the thyroid gland, congenital hypothyroidism (infants born with hypothyroidism), radiation to the thyroid gland, iodine imbalances, pituitary and hypothalamic disorders, and thyroiditis. Certain medications can also induce hypothyroidism.
Hypothyroidism risk factors include type 1 and type 2 diabetes, Rheumatoid arthritis, pernicious anemia, Sjogren syndrome, Celiac disease, and lupus.
Hypothyroidism Symptoms
Because hormones produced by the thyroid gland are used by every cell in the body, hypothyroid symptoms are vast and can include:
- Fatigue
- Brain fog
- Feeling cold often
- Hair loss
- Constipation
- Menstrual irregularities
- Weight gain
- Joint and muscle pain
- Mood changes
- Shortness of breath
In addition to the above symptoms, hypothyroidism can also increase the risk for peripheral neuropathies (nerve damage), cardiovascular disease, infertility, birth defects, and goiter (enlargement of the thyroid gland).
If left untreated, hypothyroidism can cause myxedema coma, which can be fatal. This condition requires immediate emergency care.
Top Labs to Run Bi-Annually on Your Hypothyroid Patients
Top labs to run bi-annually on hypothyroid patients include a thyroid panel, comprehensive metabolic panel, and micronutrient test.
Thyroid Panel
A complete thyroid panel, such as Doctors Data Thyroid Profile, will include TSH, T4, and T3, as well as antibodies anti-thyroid peroxidase (anti-TPO) and thyroglobulin (anti-TG) to check for autoimmune conditions. Autoimmune antibodies should only be checked bi-annually in cases of hypothyroidism caused by autoimmune conditions.
TSH
Thyroid-stimulating hormone (TSH) is produced and released by the pituitary gland in the brain. The thyroid gland should receive this hormone, and in response, the thyroid gland should produce and release T4 and T3. In hypothyroidism, however, the thyroid gland ignores TSH. The pituitary gland, in response, will continue to release TSH in higher and higher amounts. It’s like telling someone to do something, but they’re not listening; you then may continue to tell them the same thing over and over!
Standard Reference Range: 0.45 - 4.12 mlU/L
Functional Medicine Optimal Range: TSH of 0.5 - 2.5 mlU/L
Thyroxine, T4
Thyroxine is the hormone that the thyroid gland produces in the largest amount. However, it’s not as metabolically active as its sister hormone, triiodothyronine (T3). In the liver and kidneys primarily, T4 will be converted into T3. In hypothyroidism, production of T4 is lower, and thus, levels may be below the reference range.
Standard Reference Range: 0.93-1.70 mlU/L
Functional Medicine Optimal Range: 0.93-1.70 mlU/L
Triiodothyronine, T3
Triiodothyronine is converted from T4 in the liver and kidneys, as well as other peripheral sites. T3 is the primary active hormone produced by the thyroid gland and is the one taken up by most cells in the body. In hypothyroidism, we see a decrease in the amount of T4 and T3 made, which results in lower T3 levels. There may also be a problem with the conversion of T4 into T3, which would again lead to lower T3 levels.
Standard Reference Range: 2.8-4.0 mlU/L
Functional Medicine Optimal Range: 2.8-4.0 mlU/L
Anti-Thyroperoxidase (Anti-TPO)
Thyroperoxidase (TPO) is an enzyme utilized in the production of both T4 and T3. TPO is the enzyme responsible for incorporating iodine and tyrosine into thyroglobulin, forming T4 and T3. Antibodies from a person’s immune system can mistake this enzyme as a foreign invader and may begin to attack it. Anti-TPO antibodies should be below 9 IU/mlco.
Anti-Thyroglobulin (Anti-TG)
Thyroglobulin is a protein found within the thyroid gland. It serves as the foundation for the formation of thyroid hormones T4 and T3. Antibodies from a person's immune system can mistake thyroglobulin for a foreign invader. Anti-thyroglobulin levels should be less than 116 IU/mL.
Comprehensive Metabolic Panel
A comprehensive metabolic panel (CMP), such as Access Medical Laboratories CMP, assesses markers for kidney and liver health, which is important to thyroid physiology since the conversion of T4 into the active T3 occurs in these locations.
The following are kidney and liver markers found on a CMP:
Kidney Function Markers
Kidney function markers on a CMP include blood urea nitrogen, creatinine, and carbon dioxide. Kidney function can impact the conversion of T4-T3, so it’s important to assess these markers.
Blood Urea Nitrogen (BUN)
BUN is a waste product that the kidneys are responsible for excreting. BUN levels out of the reference range indicate that the kidneys are not functioning correctly.
Creatinine
Creatinine is another waste product excreted by the kidneys. Like BUN, levels of creatinine outside of the standard reference range indicate kidney malfunction.
Carbon Dioxide (CO2)
CO2 is an indicator of pH in the body. It is also a waste product that needs to be excreted, and again it is the kidney’s job to do so. However, abnormal CO2 levels are not always due to kidney problems and can also be caused by metabolic and respiratory problems.
Additionally, CMPs also check electrolyte levels, including calcium, sodium, chloride, and potassium. The kidneys maintain the amount of circulating electrolytes; thus, abnormal electrolyte levels can indicate kidney dysfunction.
Liver Function Markers
Liver function markers include albumin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and bilirubin. The liver is a site of T4-T3 conversion and abnormal liver function may impact this process; thus, it’s important to assess liver function.
Albumin
Albumin is a protein made by the liver that functions as a carrier for many hormones. It also influences fluid balance in the body. Abnormal levels of albumin can indicate the liver is not functioning properly.
Alanine Aminotransferase (ALT)
Alanine aminotransferase (ALT) is an enzyme produced in the liver. High levels of ALT out of the reference range can indicate liver damage and dysfunction.
Aspartate Aminotransferase (AST)
Aspartate aminotransferase (AST) is an enzyme produced in the liver but also in other tissues. Like ALT, high levels of AST may indicate liver dysfunction.
Alkaline Phosphatase (ALP)
Alkaline phosphatase (ALP) is found in bones, the liver, and other tissues. Thus, it is not specific to liver injury. However, it should be looked at in combination with AST and ALT if elevated to indicate the origin of its elevation.
Bilirubin
During the breakdown of red blood cells, bilirubin is formed. Elevated levels may indicate liver dysfunction but can also indicate other metabolic problems as well.
Micronutrient Panel
Micronutrient panels assess numerous vitamins and minerals on one convenient test. Micronutrients are important for thyroid functioning and physiology. Vitamins C, D, E, B2, B3, B6, iodine, iron, tyrosine, zinc, selenium, and magnesium are involved in the synthesis of thyroid hormones. For the conversion of T4 into T3, selenium and zinc are also needed. Lastly, vitamin A is necessary for thyroid hormone uptake by cells. Due to these various physiological functions, micronutrient testing, such as the Spectracell Micronutrient Test, which includes the previously mentioned micronutrients, is warranted in hypothyroidism.
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Summary
Hypothyroidism is a significant health problem that can affect daily functioning in numerous ways since thyroid hormones affect every body system. Thus, ensuring proper testing is done, and done appropriately, is essential for those who suffer from hypothyroidism in order to properly manage their care. Bi-annual labs, including thyroid panels, comprehensive metabolic panels, and micronutrient testing, can help to monitor the patient's thyroid physiology holistically and thus ensure they are feeling their best.
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