Thyroid Function Tests

Thyroid Function tests are used to tell if your thyroid gland is functioning properly by measuring the number of thyroid hormones in your blood. They are done by withdrawing blood from a vein in your arm. These blood tests help to diagnose thyroid diseases.
The TSH test and the T4 test are the two most common thyroid function tests. The TSH test is often done first because it’s the best way to initially test thyroid function. It determines whether a person has hyperthyroidism or hypothyroidism. The T4 test is known as the thyroxine test. Thyroid gland function tests are used to tell whether your thyroid is working normally.

The most common thyroid function tests are:

  • Total, or free T4 (the main thyroid hormone in your blood)
  • TSH (the hormone from the pituitary gland that stimulates the thyroid to produce T4)
  • T3 (the active form of the hormone — T4 is converted to T3)

Other thyroid tests include:

  • T3 resin uptake (an older test that is rarely used now)
  • Thyroid uptake and scan
  • Thyroid binding globulin
  • Thyroglobulin

What blood tests do doctors use to check thyroid function?

Doctors may order one or more blood tests to check your thyroid function. Tests may include thyroid-stimulating hormone (TSH), T4, T3, and thyroid antibody tests.

For these tests, a health care professional will draw blood from your arm and send it to a lab for testing. Your doctor will talk to you about your test results.

TSH test

Health care professionals usually check the amount of TSH in your blood first. TSH is a hormone made in the pituitary gland that tells the thyroid how much T4 and T3 to make.

A high TSH level most often means you have hypothyroidism or an underactive thyroid. This means that your thyroid isn’t making enough hormones. As a result, the pituitary keeps making and releasing TSH into your blood.

A low TSH level usually means you have hyperthyroidism or an overactive thyroid. This means that your thyroid is making too much hormone, so the pituitary stops making and releasing TSH into your blood.

If the TSH test results are not normal, you will need at least one other test to help find the cause of the problem.

T4 tests

A high blood level of T4 may mean you have hyperthyroidism. A low level of T4 may mean you have hypothyroidism.

In some cases, high or low T4 levels may not mean you have thyroid problems. If you are pregnant or are taking oral contraceptives NIH external link, your thyroid hormone levels will be higher. Severe illness or using corticosteroids—medicines to treat asthma, arthritis, skin conditions, and other health problems—can lower T4 levels. These conditions and medicines change the number of proteins in your blood that “bind,” or attach, to T4. Bound T4 is kept in reserve in the blood until it’s needed. “Free” T4 is not bound to these proteins and is available to enter body tissues. Because changes in binding protein levels don’t affect free T4 levels, many healthcare professionals prefer to measure free T4.

T3 test

If your health care professional thinks you may have hyperthyroidism even though your T4 level is normal, you may have a T3 test to confirm the diagnosis. Sometimes T4 is normal yet T3 is high, so measuring both T4 and T3 levels can be useful in diagnosing hyperthyroidism.

Thyroid antibody tests

Measuring levels of thyroid antibodies may help diagnose an autoimmune thyroid disorder such as Graves’ disease—the most common cause of hyperthyroidism—and Hashimoto’s disease—the most common cause of hypothyroidism. Thyroid antibodies are made when your immune system attacks the thyroid gland by mistake. Your health care professional may order thyroid antibody tests if the results of other blood tests suggest thyroid disease.

What tests are done to check thyroid function?

  • The TSH test and the T4 test are the two most common thyroid function tests. The TSH test is often done first because it’s the best way to initially test thyroid function. It determines whether a person has hyperthyroidism or hypothyroidism. The T4 test is known as the thyroxine test.

What are the 4 thyroid tests?

  • TSH – measures thyroid-stimulating hormone. It is the most accurate measure of thyroid activity.
  • T3 and T4 – measure different thyroid hormones.
  • TSI – measures thyroid-stimulating immunoglobulin.
  • Antithyroid antibody test – measures antibodies (markers in the blood)

What are the 4 thyroid tests?

Tests to evaluate thyroid function include the following
  • TSH TESTS. The best way to initially test thyroid function is to measure the TSH level in a blood sample. …
  • T4 TESTS. T4 is the main form of thyroid hormone circulating in the blood. …
  • T3 TESTS. …
  • FREE T3. …
  • REVERSE T3.

What is the most accurate test for thyroid function?

  • Assessment of TSH is the single most useful test of thyroid function in the vast majority of patients. Primary care providers should seldom need to order any other biochemical thyroid test. In most cases, the TSH will be within the normal range, and no further testing is indicated.

What are early warning signs of thyroid problems?

Early Warning Signs of Thyroid Issues
  • Fatigue.
  • Weight gain.
  • Weight loss.
  • Slowed heart rate.
  • Increased heart rate.
  • Sensitivity to heat.
  • Sensitivity to cold.

What are the symptoms of high T3?

Possible Health Risks of High T3
  • Tiredness.
  • Tremors.
  • Anxiety.
  • Trouble sleeping.
  • Weight loss.
  • Heat intolerance.
  • Rapid heartbeat.
  • Increased thirst.

What is T3 T4 TSH test?

  • A thyroid profile (T3, T4, TSH) test refers to a set of blood tests that measures the levels of the thyroid hormones secreted from the thyroid gland. It is also known as a thyroid function test.

Is TSH sufficient for thyroid tests?

  • Research finds that a simple TSH test is enough to identify hypothyroidism in 99.6% of the tests performed.

What is the best time for a thyroid test?

  • I recommend getting your thyroid function tests done first thing in the morning, bringing your medications with you, and taking them right after you have your thyroid function tests to ensure that you get accurate test results.

What should your TSH level be with no thyroid?

  • In low-risk patients, the 2015 American Thyroid Association Guidelines recommend that the goal for your initial TSH level usually be 0.5 to 2.0 mU/L, which is within the normal range. For some patients, the goal is 0.1 to 0.5 mU/L, which is just below or near the low end of the normal range.

What does an inflamed thyroid feel like?

  • Swelling in the front of the neck, just below Adam’s apple. A feeling of tightness in the throat area. Hoarseness (scratchy voice) Neck vein swelling.

What does thyroid fatigue feel like?

  • The fatigue can develop slowly or come on suddenly, leaving you barely able to lift your head off the pillow in the morning. You may feel like you can’t get through a day without a nap. You may sleep more than usual but still feel completely exhausted. You may not even have the energy to exercise.

What happens when your T3 is low?

  • Low T3 test results can indicate an underactive thyroid or hypothyroidism. Sometimes, low T3 can also indicate starvation. According to the ATA, a person can develop an underactive thyroid due to autoimmune disease, or as a result of radiation treatment or thyroid surgery.

What is the main cause of thyroid problems?

  • Problems with the thyroid can be caused by: iodine deficiency. autoimmune diseases, in which the immune system attacks the thyroid, leading either to hyperthyroidism (caused by Graves’ disease) or hypothyroidism (caused by Hashimoto’s disease) inflammation (which may or may not cause pain), caused by a virus or .

When T3 and T4 are normal but TSH is high?

  • When the thyroid gland becomes inefficient such as in early hypothyroidism, the TSH becomes elevated even though the T4 and T3 may still be within the “normal” range.

What is the difference between T3 and T4 thyroid tests?

  • Thyroxine (T4) is responsible for your metabolism, mood, and body temperature, among other things. T3, too, is made in the thyroid gland, and it can also be made in other tissues within the body by converting T4 (in a process called deiodination) into T3.

Why is my TSH low but my T3 and T4 are normal?

  • A low TSH with normal free T4 and T3 levels is consistent with subclinical hyperthyroidism. Some patients with nodular goiter and Graves’ disease, particularly early in the disease course, will have predominant elevations in T3 due to increased conversion of T4 to T3 and a disproportionate increase in T3 secretion.

Is TSH 5.6 normal?

  • Most laboratories classify normal TSH levels as between 0.4 and 4.5 milliunits per liter (mU/L), according to the American Thyroid Association (ATA). A normal TSH level in most cases, usually indicates that you don’t have a thyroid problem.Jan 20, 2020

Is TSH alone enough?

  • TSH alone would be a sufficient screening test for thyroid hormone abnormalities. Thyroid problems are common in adults. There are different recommendations on how to screen for abnormal thyroid hormone levels that may indicate a thyroid problem, and therefore, there are many variations in how this is done.

How many hours of fasting is required for a thyroid test?

  • Usually,no special precautions including fasting need to be followed before taking a thyroid test. However, your pathologist can guide you better. For example, if you have to undergo some other health tests along with thyroid hormone levels, you may be asked to fast for 8-10 hours.

Should a thyroid test be done on empty stomach?

  • Yes, thyroid tests should be done empty stomach for best results.

What are the symptoms of thyroid problems in females?

Symptoms
  • Fatigue.
  • Increased sensitivity to cold.
  • Constipation.
  • Dry skin.
  • Weight gain.
  • Puffy face.
  • Hoarseness.
  • Muscle weakness.

What are the side effects of not having a thyroid gland?

  • Side effects of thyroid removal are hypothyroidism (low thyroid hormone), low calcium, tremor, and spasms. The thyroid is a butterfly-shaped endocrine gland located below Adam’s apple in the lower part of the neck and wraps around the windpipe (trachea).

What is life like without a thyroid?

  • Aside from having your thyroid levels tested regularly and taking medication daily to give your body the thyroid hormone it needs, people without a thyroid live an otherwise normal life. Adjusting to life without your thyroid means taking medication and checking in with your doctor. Most people adjust easily.

Does your neck hurt with thyroid problems?

  • The most obvious symptom of subacute thyroiditis is a pain in the neck caused by a swollen and inflamed thyroid gland. Sometimes, the pain can spread (radiate) to the jaw or ears. The thyroid gland may be painful and swollen for weeks or, in rare cases, months.

Does your throat hurt with thyroid problems?

  • An under-active thyroid can mess with your sense of taste and smell. If you can’t stop eating, it may be hyperthyroidism — or an overactive thyroid. Neck or throat discomfort – A lump in your throat, changes in your voice, or even a goiter could be a sign of a thyroid disorder.

Can thyroid cause throat and ear pain?

  • There are several signs that might indicate thyroid cancer. These include a lump or swelling in the neck; neck, throat, or ear pain; difficulty swallowing and/or breathing; hoarseness; chronic cough; swollen lymph nodes, and wheezing.

How can the thyroid affect your eyes?

  • Underactive thyroid (hypothyroidism) isn’t usually associated with eye disease. In severe cases, however, hypothyroidism may cause swelling around the eyes and a loss of hairs in the outer part of the eyebrows.

Can thyroid cause dizziness balance problems?

  • Some endocrine diseases, such as hypothyroidism, can lead to balance disturbances and thus cause dizziness by affecting the labyrinthic functions of the vestibular system. Inflammatory or metabolic changes in patients with thyroid disease may impact inner ear inflammation and endolymphatic flow homeostasis.

Does thyroid affect sleep?

  • If your thyroid makes too little hormone, it’s a more common condition called hypothyroidism. You might have trouble falling asleep or not be able to stay asleep long enough to feel fully rested. Hypothyroidism also can affect your sleep by making you feel too cold or causing joint or muscle pain.
How can I boost my T3 naturally?
  • Selenium is a trace element that is needed for the conversion of T4 to T3 so ensure that you eat selenium food sources daily to support this conversion and optimal levels. Sources include brazil nuts, walnuts, mushrooms avocados, fish and cereal grains.

How can I increase my T3 levels?

  • Several health studies have shown that T3 and T4 hormone levels increase with exercise. Beyond helping to stimulate thyroid production, exercise also helps to counteract many of the side effects of hypothyroidism such as gaining weight, loss of muscle, depression, and low energy levels.

Does low T3 cause weight gain?

  • Kitahara, if someone has low thyroid function, their TSH is high, and the thyroid hormones known as T3 and T4 are low—and weight gain often occurs.

Does stress cause thyroid?

  • Stress alone will not cause a thyroid disorder, but it can make the condition worse. The impact of stress on the thyroid occurs by slowing your body’s metabolism. This is another way that stress and weight gain are linked.

At what age do thyroid problems start?

  • The disease is hereditary and may develop at any age in men or women, but it’s much more common in women ages 20 to 30, according to the Department of Health and Human Services. Other risk factors include stress, pregnancy, and smoking.

Who is most at risk for thyroid problems?

You may be at a higher risk of developing thyroid disease if you:
  • Have a family history of thyroid disease.
  • Have a medical condition (these can include pernicious anemia, type 1 diabetes, primary adrenal insufficiency, lupus, rheumatoid arthritis, Sjögren’s syndrome, and Turner syndrome).

What if TSH is high in thyroid tests?

  • High TSH levels can mean your thyroid is not making enough thyroid hormones, a condition called hypothyroidism. Low TSH levels can mean your thyroid is making too much of the hormones, a condition called hyperthyroidism.

What is considered a dangerously high TSH level?

  • Experts don’t agree on which TSH levels should be considered too high. Some suggest that TSH levels of over 2.5 milliunits per liter (mU/L) are abnormal, while others consider levels of TSH to be too high only after they have reached 4 to 5 mU/L.
7 Early Warning Signs of Thyroid Issues
  • Fatigue.
  • Weight gain.
  • Weight loss.
  • Slowed heart rate.
  • Increased heart rate.
  • Sensitivity to heat.
  • Sensitivity to cold.

Subclinical (borderline) hypothyroidism

  • Some people have a mildly underactive thyroid, with few or no symptoms. Doctors call this subclinical hypothyroidism. If you have this, your blood test will show that your TSH is raised but your free T4 is normal. This is fairly common, especially in older people.

What is the best time for a thyroid test?

  • I recommend getting your thyroid function tests done first thing in the morning, bringing your medications with you, and taking them right after you have your thyroid function tests to ensure that you get accurate test results.
Symptoms of underactive thyroid
  • tiredness.
  • being sensitive to cold.
  • weight gain.
  • constipation.
  • depression.
  • slow movements and thoughts.
  • muscle aches and weakness.
  • muscle cramps.

What is Hashimoto’s Disease

  • This is the most common reason that Americans have low thyroid levels. It’s an autoimmune disease. If you have one, your immune system attacks your body’s healthy cells. If you have Hashimoto’s disease, it destroys the cells that make thyroid hormone.

What foods to avoid if you have no thyroid?

Which nutrients are harmful?
  • Soy foods: tofu, tempeh, edamame, etc.
  • Certain vegetables: cabbage, broccoli, kale, cauliflower, spinach, etc.
  • Fruits and starchy plants: sweet potatoes, cassava, peaches, strawberries, etc.
  • Nuts and seeds: millet, pine nuts, peanuts, etc.