Thyroid Lab Tests

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  1. THYROID Panel (TSH + Free T3 + Free T4)
    Special Price $82.95 Regular Price $101.15

    This panel includes comprehensive testing of the thyroid stimulating hormone (TSH) in addition to free thyroxine (T4) and free triiodothyronine (T3). This thyroid panel offers a lower cost than buying each hormone separately.  If you take biotin, please wait at least 8 hours to get blood drawn. A study found that TSH was suppressed in all subjects after food, so fasting may be suggested although it is not reqired by Quest. Free T4 and Free T4 values did not change significantly after eating.

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  2. Iodine Blood Test
    $62.51

    Iodine, Serum/Plasma - Iodine is an essential element that is required for thyroid hormone production. The measurement of iodine serves as an index of adequate dietary intake and iodine overload, particularly from iodine-containing drugs such as Amiodarone.

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  3. Thyroid Antibody Panel
    $62.51

    These two tests measure antithyroglobulin antibodies and Anti-TPO antibodies that are commonly present in patients with Hashimoto's thyroiditis, Graves disease and other thyroid-related conditions. Antibodies against the protein thyroglobulin can result in the destruction of thyroid cells. TPO antibodies are created when the immune system of a person targets by pure error elements of the thyroid gland or protein, leading to chronic thyroid inflammation, tissue damage, and damage to the thyroid function. Leaving this untreated may cause severe health issues. 

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  4. Thyroxine-binding Globulin (TBG), Serum
    $107.41

    Thyroxine-binding globulin (TBG) is a globulin that binds thyroid hormones in circulation. It is one of three transport proteins (along with transthyretin and serum albumin) responsible for carrying the thyroid hormones thyroxine (T4) and triiodothyronine (T3) in the bloodstream. Of these three proteins, TBG has the highest affinity for T4 and T3 but is present in the lowest concentration. Despite its low concentration, TBG carries the majority of T4 in the blood plasma.

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  5. THYROID Panel (TSH + Free T3 + Free T4)

    As low as $82.95 Regular Price $101.15

    This panel includes comprehensive testing of the thyroid stimulating hormone (TSH) in addition to free thyroxine (T4) and free triiodothyronine (T3).

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  6. THYROID Panel - COMPREHENSIVE
    $300.63

    This test panel includes most tests needed to more deeply explore the possibility of hypothyroidism and/or Hashimoto's disease diagnosis. It includes: TSH, Free T3, Free T4, Reverse T3, Thyroglobulin Antibody and Thyroid Peroxidase Antibody (Anti-TPO). If you are taking biotin, please stop it 72 hours before the blood draw since it may interfere with hormone blood tests. A study found that TSH was suppressed in all subjects after food, so fasting may be suggested although it is not reqired by Quest. Free T4 and Free T4 values did not change significantly after eating.

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  7. THYROID Stimulating Hormone-TSH
    $17.00

    The thyroid stimulating hormone (TSH) is produced and secreted by the pituitary gland and stimulates the thyroid to produce T3 and T4. When TSH is elevated, low thyroid function may be indicated. If TSH is low it is indicative of high thyroid function. A study found that TSH was suppressed in all subjects after food, so fasting may be suggested although it is not reqired by Quest. Free T4 and Free T4 values did not change significantly after eating.

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  8. Free Triiodothyronine T3
    $43.88

    T3 or triiodothyronine is the active form of the thyroid hormone. T3 acts as a metabolic throttle for fueling all of the daily cellular functions. Free T3 is the unbound portion of T3 that is biologically active.

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  9. Free Thyroxine T4
    $38.08

    The thyroid gland produces and secretes T4, otherwise known as thyroxine. Proteins bind to T4 and carry it throughout the bloodstream. Once in the tissues, T4 is released from the proteins and is now free to convert into the more active form called T3. For this reason, many doctors believe that measuring free T4 is a more sensitive test for thyroid hormone production.

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  10. Reverse T3 Lab Test
    $68.83

    The reverse T3 test has to be done at the same time you do the free T3, and you then measure the ratio between the two by dividing the RT3 into the Free T3. The body produces the benign RT3 naturally to rid itself of excess of T4, but in some cases, such as high or low cortisol, RT3 is produced in excess which can clog cell receptors from receiving T3. FT3 is usually twenty or more times higher than RT3.

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  11. Thyroglobulin Antibody
    $118.31

    This test measures thyroglobulin antibodies commonly present in patients with Hashimoto's thyroiditis. Antibodies against the protein thyroglobulin can result in the destruction of thyroid cells. This destruction can lead to hypothyroidism.

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  12. THYROID Peroxidase Antibody (Anti-TPO)
    $29.87

    The determination of TPO antibody levels is the most sensitive test for detecting autoimmune thyroid disease (eg, Hashimoto's thyroiditis, idiopathic myxedema, and Graves disease) and detectable concentrations of anti-TPO antibodies are observed in most patients with these disorders. The highest TPO antibody levels are observed in patients suffering from Hashimoto thyroiditis. In this disease, the prevalence of TPO antibodies is about 90% of cases, confirming the autoimmune origin of the disease. These autoantibodies also frequently occur (60%–80%) in the course of Graves disease.

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Have you noticed any of the following symptoms?

- Feeling tired all the time, even after a full night of sleep or a nap

- You feel "fuzzy", like there is wool in your brain

- Feeling moody or depressed

- Your sex drive has tanked

- Nerves, anxiety, the "jitters"

- Your digestive system isn't working properly

- You've lost your appetite, or your sense of smell or taste has changed

These are just a few symptoms of thyroid problems.

What is the Thyroid Gland?

The thyroid is a butterfly-shaped endocrine gland that is approximately two inches long and is located at the front of your neck below your Adam's apple. The thyroid plays a major role in growth and metabolism by releasing the hormones thyroxine or T4 and triiodothyronine or T3, which regulate your body's ability to convert calories and oxygen into energy. The hypothalamus in your brain produces thyrotropin-releasing hormone or TRH, which stimulates the release of thyroid stimulating hormone or TSH from your pituitary gland. TSH then travels to your thyroid and prompts the release of T4 and T3 into your bloodstream. Under normal conditions, your thyroid produces approximately 80% T4 and 20% T3, with T3 being four times more potent than T4.

Every cell in your body has receptors for thyroid hormones affecting your cardiovascular system, bone metabolism, protein synthesis, body temperature regulation, cholesterol production, glucose metabolism, cognitive function, and your gastrointestinal tract. An estimated 20 million Americans have some form of thyroid disorder with women being impacted more often than men.

What is Hypothyroidism and What Thyroid Tests Diagnose it?

Hypothyroidism is the most common thyroid disorder characterized by fatigue, weight gain, constipation, hair loss, dry skin, cold intolerance, irregular menstruation, depression, muscle pain, and cognitive impairment. Hypothyroidism is an underactive thyroid gland producing an insufficient amount of hormones necessary for optimal metabolic function. The most common cause of hypothyroidism is Hashimoto's thyroiditis, which is an autoimmune disorder where the body produces antibodies that attack and destroy thyroid gland tissue.

Other causes of hypothyroidism include an iodine deficiency, a pituitary tumor, radiation therapy on your face, neck or chest, pregnancy and childbirth, the aging process, and an under conversion of T4 to T3 due to inflammation, stress, a selenium deficiency, and overexposure to fluoride, chlorine or mercury. If you're experiencing any of the symptoms of hypothyroidism, you should request that your family physician order blood tests that include thyroid stimulating hormone, free T4, free T3, reverse T3, and thyroid antibodies, if he or she suspects Hashimoto's. When interpreted correctly, lab results can help to determine the root cause of your thyroid dysfunction and the appropriate clinical interventions.

Why Is It Important to Understand Your Thyroid Tests?

With so many different symptoms and so many different organ systems potentially affected by thyroid system dysfunction, one might think that a diagnosis would be easy. However, in spite of the available blood tests for thyroid/pituitary/liver/adrenal function, the diagnosis is often missed. One of the most common misconceptions regarding thyroid function is the assumption that any reliance on the requirement that the diagnosis of hypothyroidism depends on an elevated TSH level. Normally, the pituitary gland will secrete Thyroid stimulating hormone (hence TSH) in response to a low circulating thyroid hormone level.

This is thought to reflect the pituitary's sensing of inadequate thyroid hormone levels in the blood that would be consistent with hypothyroidism. There is no question that an elevated TSH can confirm the diagnosis of hypothyroidism, but it is far too insensitive a measure, in other words, the vast majority of patients who have hypothyroidism do not have an elevated TSH level. Some have suggested that perhaps the upper limit of what is considered normal is too high, instead of the normal TSH range being from 1.0-4.5, the range of normal for TSH should be 0.5-2.5. In that way, more patients would be considered hypothyroid.

Furthermore, the lab level of TSH tends to vary throughout different times during the day making it less useful to rely on as the average level. MSG (monosodium glutamate) and stress tend to lower the TSH level, for example.

The most commonly used tests of thyroid hormone levels (note that I use the term level rather than function because the two are not always equal) are the T4 (or total T4), T3-uptake, FTI (also called the T7 or Free Thyroxine Index), and total T3 (sometimes called the T3-by-RIA). These tests are also unreliable because they do not reflect the hormone level that is actually available for action. Only the free T4 and free T3 are available to act on the cells. The total T4 and total T3 (as is most commonly measured) is a mixture of protein-bound T4 and T3 (and therefore not available to the cells) and the free T4 and T3. A large percentage of patients have low levels of the free T4 and free T3 even when all the other more commonly used tests are normal. Complicating the problem is the fact that these symptoms may present themselves while all the usual blood tests (TSH, FI, Total T3, etc) appear to be normal. When patients with Free T4 and Free T3 hormone levels below normal with or without an elevated TSH are given appropriate therapy, many report a tremendous improvement in the symptoms classically associated with hypothyroidism. Even when the lab work does not indicate low thyroid levels, many patients appear to fit the profile for low thyroid action. In fact, many of the best thyroidologists use the response to therapy as the major determinant of whether or not the patient was in fact hypothyroid. The diagnosis was confirmed by the response to the proper therapy. Even many of the most prestigious textbooks validate this approach.

HOW DOES DISCOUNTEDLABS.COM WORK?

 

1-     Go to the "Find a Location" page to find the closest lab location. Please only go to “Quest Diagnostics” locations.

2-     Go to "Choose a Test" and add your selection (s) in the shopping cart. You can also save money by buying bundled lab test panels.

3-     If you have a discount coupon code, add it to your cart.

4-     Pay using a credit card.

5-     You will receive three emails: an order confirmation, detailed instructions, and a lab requisition form by email during business hours (Monday-Friday 9-5 PM Central).

6-     Print the lab requisition form (PDF file).

7-     Take that form to the closest Quest Diagnostics location with a picture ID. Get your blood drawn.  

8-     Your results will be ready within 5-7 business days (depending on the test). You will received them by email.