Prior to the current use of TSH (thyroid stimulating hormone) to assess thyroid function, doctors used much simpler, yet highly effective ways to grade thyroid function. Doctors in the 1940’s used signs and symptoms to make a working diagnosis and relied on basal metabolic rate to confirm the diagnosis. Basal body temperature, metabolism and heart…

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A diagram of the thyroid gland with a text bubble saying what is thyroid hormone conversion?

Normal Thyroid Physiology When we refer to ‘thyroid hormones’ we are talking about T3 and T4. They are the ones the thyroid gland secretes. T4 is more stable in the blood and better for transport around the body; T3 is more biologically active. Of the thyroid hormones produced, 85-90% is T4 and 10-15% is T3.…

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doctor confused by thyroid blood work

Normal Lab Testing Thyroid Function Tests (TFTs) are among the most commonly requested lab investigations. For most of the population, interpreting the lab work is fairly straightforward when we look at a combination of TSH, T4 and perhaps T3. Learn more about the routine lab work here. For a quick review of Basic Thyroid Anatomy…

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Gloved hand hold an empty vial with text bubble saying confusing thyroid blood work: assay intereference

When your doctor assesses or treats your thyroid function, they will usually rely on blood work. Sometimes, we see confusing blood test results, which don’t follow the predictable relationships between the various hormones being tested. Normal Testing Usually, testing is straightforward, and results align with symptoms. In cases of hypothyroidism, we expect elevated TSH and…

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suprised doctor looking at a pile of medications, which are causing confusing thyroid blood work

Thyroid lab tests are commonly run. Oftentimes, the lab results make sense and treatment is straightforward. However, there are a lot of cases where the lab results don’t correlate with your symptoms, or the lab results contradict each other. Click here to learn more about how thyroid test results can be confusing. This article focuses…

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Man palpating his neck with thyroid gland superimposed on throat and text bubble saying confusing thyroid blood work: non-thyroidal illness

When your doctor assesses or treats your thyroid function, they will usually rely on blood work. In a lot of patients suffering from hypothyroidism, blood test results are confusing, and don’t follow the expected findings; one cause is non-thyroidal illness. Normal Testing Usually, testing is straightforward and results align with symptoms. In cases of hypothyroidism, we…

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collage of dietary goitrogens related to thyroid function including soy, cruciferous vegetables, sweet potato, brussel sprouts

To Summarize: Goitrogens are substances which may interfere with thyroid function They may interfere with the thyroid gland and how the thyroid hormones are made Certain foods contain dietary goitrogens. Those foods are otherwise healthy, good foods. People with low functioning thyroid need to be aware of these, and may need to avoid them Thyroid…

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Skeleton with thyroid gland and text bubble saying a review of healthy thyroid function: anatomy and physiology

This introductory article is one of many in-depth articles on thyroid function and focuses on normal thyroid anatomy and physiology. Learn more about hypothyroid, hyperthyroidism and testing by clicking the links. Basic Physiology and Anatomy The most important anatomical structures are shown in the image below: The hypothalamus creates a hormone called thyrotropin-releasing hormone (TRH).…

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Vials of blood held in a gloved hand with text bubble saying is TSH testing enough?

In ‘ideal’ thyroid physiology, a patient’s symptoms would be reflected in their blood work. As doctors, we learn low TSH is associated with hyperthyroidism and high TSH is associated with hypothyroidism. For a full recap on normal thyroid physiology, click here. Usually, thyroid lab test results match the symptoms. Ideal Situations Thyroid Stimulating Hormone (TSH)…

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