-
- By: Healthy Beings Staff
- |
- Thyroid Health
- |
- January 6, 2022
- |
- 5 Min read
The thyroid is a small, butterfly-shaped gland in your neck located just above the collarbone that plays a significant role in releasing and regulating thyroid hormones that control metabolism.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, the most common thyroid diseases include:
- Hyperthyroidism, an overactive thyroid
- Hypothyroidism, an underactive thyroid
- Graves’ disease, the most likely culprit behind hyperthyroidism
- Hashimoto’s disease, the most likely culprit behind hypothyroidism
- Thyroid nodules
- Thyroid cancer
If a doctor is concerned about your thyroid hormone levels, there is a broad range of screening tests they may order to pinpoint the root of the problem. Thyroid function tests fall into three categories per Johns Hopkins Medicine: thyroid scans using blood tests, ultrasound exams and radioactive elements.
Blood Tests for the Thyroid
In some cases, your doctor may choose to order a blood test to check your thyroid function. They may even order multiple tests. The Cleveland Clinic reports that the thyroid blood tests include:
- TSH Tests. A thyroid-stimulating hormone (TSH) test is commonly the first test that doctors order. It is released from the pituitary gland and reflects how well the pituitary gland is working. The higher the TSH in the blood, the more likely the gland is not making enough thyroid hormone. The lower the TSH, the more likely the thyroid is producing too much hormone.
- T4 Tests. Because T4 is the primary form of thyroid hormone in the blood, it is a preferred testing level. It is the most abundant form of the thyroid hormone and requires the liver to activate it into T3. High blood levels of T4 suggest hyperthyroidism, whereas low blood levels of T4 suggest hypothyroidism. However, oral contraceptives and corticosteroids can affect T4 levels, so be sure to tell your healthcare provider any medications you are taking so that these factor into the test results.
- Reverse T3 (rT3). Our current understanding of the thyroid suggests that rT3 levels can elevate if the body is experiencing a crisis. For example, animal studies show that rT3 helps the body repair after a stroke, so there is a higher concentration of rT3 in the blood. However, what is currently unclear is whether or not the same is true for humans.
- Thyroid antibody: When correctly functioning, the immune system protects us against foreign invaders such as bacteria and viruses. Unfortunately, hypothyroidism or hyperthyroidism can trigger the immune system to attack the thyroid. This creates antibodies such as thyroid peroxidase antibody and thyroglobulin antibody. Identifying these antibodies can result in a correct diagnosis of Hashimoto’s disease, also called hypothyroidism due to autoimmune thyroiditis.
Another option is a home test kit made by Thorne Research. This test also measures key biomarkers that reflect thyroid health and function using a blood spot test. It measures:
- TSH
- Free T3, the active form of the thyroid hormone
- T4
- Thyroid antibody
The results from this test are reviewed by an independent, board-certified physician and include a personalized health plan. This test is as accurate as a standard blood test you would get from your doctor.
Thyroid Ultrasound
Like an ultrasound during pregnancy, an ultrasound scan of the thyroid gland uses high-frequency sound waves to create an image of the organ.
The image allows healthcare providers to identify any abnormal enlargement or nodules. If a biopsy is necessary to diagnose or rule out thyroid cancer, an ultrasound can also guide the biopsies of the concerning nodules, cysts, or tumors.
Typically, a doctor only orders a thyroid ultrasound if thyroid function tests return abnormal or if your physician feels a growth on your thyroid while examining your neck.
The test itself is non-invasive, according to Healthline. Your provider will likely apply a gel to the area, which helps the ultrasound probe move smoothly over your neck.
Images will appear on a screen in real-time, and you should not feel any pain during the test.
Radioactive Iodine Thyroid Test
Radioactive Iodine Uptake (RAIU) is a test of thyroid function. Patients are typically asked to fast for 8 hours before the test.
The RAIU test measures how much radioactive element is accumulated in the thyroid gland. If too much of the element accumulates in the thyroid, this suggests an overactive thyroid (hyperthyroidism). However, if there is low uptake, the results may indicate hypothyroidism. UCLA Health reports that RAIU is administered via pill, and the results are measured anywhere between 6 and 24 hours later.
Iodine is not the only element that may be used for this test. Other commonly used elements include Selenium or Technetium.
Final Thoughts
If you are concerned about your thyroid or thyroid function, it is recommended to talk with your health care provider. They can help determine which tests will be the most helpful in finding the source of the issue. Most of the time, a blood test is the first step.
