Do You Have Hyperthyroidism? How To Test Your Thyroid Function

If you experience symptoms of hyperthyroidism, your doctor may order a range of tests to officially diagnose you with the condition. This guide will help you to understand what hyperthyroidism is and what you can expect when seeking a diagnosis from your doctor.

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What is hyperthyroidism?

Hyperthyroidism is a condition characterized by an overactive thyroid, which means it produces too much thyroid hormone. The thyroid is a butterfly-shaped gland in the neck that sits behind where Adam's apple is in males or would be in females.

This gland regulates and releases the thyroid hormone, responsible for how energy is used in your body. Excessive thyroid hormones can temporarily increase your energy, followed by a period of intense lethargy.

As hyperthyroidism can negatively affect your life in various ways, early diagnosis is important to enable you to recover sooner.


Hyperthyroidism is associated with a variety of symptoms, including:

  • Rapid heartbeat

  • Anxiety

  • Irritability

  • Difficulty sleeping

  • Irregular menstrual cycles

  • Increased sweating

  • Hand tremors 

  • Smooth, moist, and warm skin

  • Brittle hair

  • Weight loss without trying

  • Increased hunger

  • More frequent bowel movements

If your body produces too much of the thyroid hormone, it speeds up many bodily functions, including heart rate and digestion. This can lead to rapid weight loss despite eating the same amount. These symptoms are more evident in young and middle-aged people. 

How is thyroid function tested?

If you believe you might have hyperthyroidism or other thyroid problems, observe and take note of your symptoms, then make an appointment to speak with your doctor. Your doctor will enquire about any symptoms of hyperthyroidism you may be experiencing, your medical history, and your family history.

Next, they will conduct a physical exam, where they may listen to your heartbeat, feel your neck for swelling, and perform other examinations to help them determine whether any further tests are necessary.

Your doctor will also consider any risk factors relevant to you that may increase your likelihood of developing hyperthyroidism, including:

  • Being over 60 years old

  • Being born a female

  • Having a personal history of autoimmune diseases

  • Having a family history of thyroid disease

If your doctor believes you may have hyperthyroidism, they can order blood tests, a radioiodine uptake test, a thyroid scan, or a thyroid ultrasound to confirm a diagnosis of hyperthyroidism.

Blood tests for thyroid function

Blood tests for hyperthyroidism involve drawing a small amount of blood to assess a few different thyroid measures.

Testing for TSH (thyroid-stimulating hormone) levels is the first blood test to check your thyroid function. TSH regulates how much thyroid hormone is produced by the thyroid gland.

A low level of TSH indicates that your thyroid is overactive. This is because an overactive thyroid produces too much of the thyroid hormone, which in turn suppresses TSH levels.

If your TSH levels are low, your doctor will order T3 and T4 tests. T3 and T4 control your body's metabolic rate. High T3 and T4 can shift your body into overdrive, producing feelings of high energy, anxiety, and tremors.

While these tests can confirm a hyperthyroidism diagnosis, your doctor will most likely order additional tests to determine the cause of your hyperthyroidism.

Radioiodine uptake test and thyroid scan

If your blood tests indicate that you have hyperthyroidism, your doctor will order a radioiodine uptake test and thyroid scan to further assess the cause of your hyperthyroidism.

This test involves ingesting a small dose of radioactive iodine to see how much of it is absorbed by your thyroid gland. After about 6 to 24 hours, your doctor will be able to see how much iodine your thyroid has collected.

Abnormally high iodine absorption indicates that your thyroid produces too much thyroxine. This tends to be the case if you have Graves’ disease or thyroid nodules.

A thyroid scan involves a healthcare professional taking specialized images of your thyroid with a gamma camera after ingesting radioactive iodine. This test can reveal if you have inflammation, swelling, or nodules on your thyroid that can impact its function.

Thyroid ultrasound

Alternatively, your doctor may suggest a thyroid ultrasound to check for nodules or other abnormalities with your thyroid. This test is often used if you are pregnant, lactating, or cannot safely consume radioactive iodine for any other reason. This quick test involves your doctor using sound waves that display an image of your thyroid on a screen.

Hyperthyroidism treatment

If your doctor has diagnosed you with hyperthyroidism, they will work with you to formulate the best treatment plan. Typically, once you begin treatment, you will start to feel better within a few weeks.

Common treatments include:

  • Medications Antithyroid medications (that stop the production of new thyroid hormones) or beta-blockers (that reduce symptoms like rapid heart rate and tremors).

  • Radioactive iodine — To reduce the number of overactive thyroid cells in the thyroid gland.

  • Surgery — To remove all or part of the thyroid gland if you are treatment-resistant or have a goiter that is causing symptoms that may lead to breathing or swallowing difficulties.

Each treatment has its benefits and side effects, so it is important to speak with your doctor about which treatment may be right for you.

The lowdown

Hyperthyroidism is a serious medical condition in which your thyroid gland becomes overactive and produces too much thyroid hormone, resulting in increased metabolism and other symptoms.

The good news is that hyperthyroidism is a manageable condition, and it is possible to recover within a few weeks if detected early.

If you have concerns about your thyroid function, make an appointment with your doctor as soon as possible to seek a diagnosis and discuss an appropriate treatment plan.

Other sources:

  • Thyroid tests | (NIDDK) National Institute of Diabetes and Digestive and Kidney Diseases

Have you considered clinical trials for Hyperthyroidism?

We make it easy for you to participate in a clinical trial for Hyperthyroidism, and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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