How Is Hyperthyroidism Diagnosed?

Your thyroid is an important organ in your body. When it doesn't work properly, other systems in your body could be affected, including your cardiovascular system and metabolism. Because of this, it's important to schedule a doctor's appointment if you notice signs of an overactive thyroid gland to receive a diagnosis and get treatment as quickly as possible. Here's what you should know about diagnosing hyperthyroidism and finding the treatment you need.

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.

What is the thyroid?

Your thyroid is a small, butterfly-shaped gland that's located low down at the front of your neck. It is responsible for producing thyroid hormones, called thyroxine (T4) and triiodothyronine (T3). These hormones work with other organs and systems in your body to ensure they work properly, helping to regulate your heart rate, metabolism, and digestive system. When your thyroid produces either too many of these hormones or not enough, you may be diagnosed with thyroid disease.

What is hyperthyroidism?

Hyperthyroidism, also called an overactive thyroid, occurs when your thyroid produces more hormones than your body needs. When this occurs, other systems in your body could speed up, which can cause negative side effects.

Some symptoms of hyperthyroidism include:

Hyperthyroidism can be caused by a number of factors, including:

How is hyperthyroidism diagnosed?

While you may recognize the signs of hyperthyroidism on your own, it is best for a doctor to formally diagnose an overactive thyroid gland.

Your doctor will start by reviewing your medical history, discussing your symptoms, and performing a physical examination. If they suspect that you could have an overactive thyroid gland, they will likely perform other tests to confirm this.

These tests include:

Blood tests

Hyperthyroidism is most commonly diagnosed by measuring the T4 and TSH levels in your blood. Thyroid-stimulating hormone (TSH) is produced by the pituitary gland in your brain and encourages your thyroid to produce an adequate amount of hormones.

 When your thyroid doesn't produce enough T4, your TSH will be high. When your thyroid produces too much T4, your TSH will be low. If your TSH is too low or high, it could indicate that your thyroid isn't working properly.

A normal TSH level ranges from 0.4 – 4.0 mIU/L. If your TSH is lower than 0.4 mIU/L, you may have an overactive thyroid.

Iodine uptake scan

In this scan, you will be given a small amount of iodine to drink. After a set amount of time, such as four, six, or 24 hours, the iodine that remains in your thyroid gland will be measured in a scan of the thyroid gland. The iodine that you drink for the purposes of this test will not cause you any harm. 

Thyroid scan 

This test is often done at the same time as the iodine uptake scan. After drinking iodine, scans will be taken of your thyroid in order to get a clear image of it. A thyroid scan can be done with or without the iodine uptake scan.

How is hyperthyroidism treated?

If you are diagnosed with an overactive thyroid gland, there are many options to manage the condition.

Your healthcare provider will create a treatment plan that is based on your unique circumstances, including the severity of your condition, your age, the cause of the hyperthyroidism, and the medications you're currently taking.

Some common treatments for an overactive thyroid include:

Anti-thyroid medications

These medications are used to prevent your thyroid from over-producing hormones. They usually take several weeks or months to work and often require people to stay on them for a minimum of a year.

Methimazole and propylthiouracil are two examples of anti-thyroid medications. While they are effective, they also come with serious risks, including making people more likely to develop infections, liver failure, or even death.

However, these side effects are not common and your doctor will be reviewing you closely to see if you develop any troubling side effects whilst taking this medication.

Radioactive iodine

This is used to help your thyroid shrink. It usually takes months to reduce your hyperthyroidism symptoms, and even longer for your body to get rid of the excess iodine.

Additionally, taking radioactive iodine for too long can lead to hypothyroidism, in which your thyroid doesn't produce enough hormones. This could require you to take a synthetic thyroid hormone medication, such as levothyroxine, for the rest of your life.


For people who can't take anti-thyroid medications or don't want to take radioactive iodine, removing part or all of your thyroid may be beneficial. If your entire thyroid is removed, you'll have to take levothyroxine daily for the rest of your life.


While these medications are most commonly used for high blood pressure, they can help reduce the symptoms of hyperthyroidism, including heart palpitations. They can be used along with other medications to help you feel better until your hormone levels are regulated. 

When to speak to a healthcare professional

If you are experiencing one or more symptoms of hypothyroidism, don't put off scheduling an appointment with your healthcare provider.

Seeking professional care sooner rather than later can determine if you do have an overactive thyroid and what may be causing it.

If left untreated, hyperthyroidism can lead to more serious health concerns that range from the uncomfortable to the more dangerous.

The lowdown

Hyperthyroidism is a thyroid disorder that occurs when your thyroid makes more hormones than your body needs. Graves' disease is the most common cause, however, other factors could lead to hyperthyroidism.

If you experience one or more symptoms of an overactive thyroid, such as insomnia, weight loss, or heart palpitations, it's important to schedule an appointment with your doctor.

They can diagnose your condition by performing a physical examination and performing some tests, including blood tests (to check your TSH level), iodine uptake scans, and/or a thyroid scan.

Treating hyperthyroidism is possible with the help of anti-thyroid medications, radioactive iodine, or surgery.

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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