Thyroid Function Test (T3, T4, TSH)

A thyroid function test refers to a group of blood tests used to evaluate the functioning of the thyroid gland. To check for hyperthyroidism or hypothyroidism, your healthcare providers monitor the levels of thyroid hormones in your blood through this test. It also helps in knowing whether your thyroid gland is working well or not.

What Is Thyroid Function?

In your neck, there is a gland called the thyroid gland that performs various bodily functions. It secretes the hormones- T3 or triiodothyronine and T4, also known as thyroxine. They regulate processes such as:

• Regulate the rate at which your body consumes calories or energy. Therefore it can affect weight
• Slows or increases your heart rate
• Control body temperature
• Affect brain development and muscle contraction
• Manage skin and bone replacement in your body- a normal process in which your body replaces dying cells.

When your thyroid gland does not function well, the hormone secretion gets affected, and your bodily functions too. Sometimes, your thyroid gland produces too many thyroid hormones, leading to hyperthyroidism. And in hypothyroidism, your thyroid gland produces too few thyroid hormones.

What Is Thyroid Function Test Used For?

The thyroid function test is used to measure levels of thyroid hormones. It measures the levels of serum T3, T4, and TSH. They help make the final diagnosis of whether the patient has hypothyroidism or hyperthyroidism, or any other health condition.

When Should I Get A Thyroid Function Test?

When your thyroid gland does not work well, you have noticeable symptoms. Your healthcare provider will advise you to get a thyroid function test done. You must get them done if you have the following symptoms:

• Unexplained weight loss or weight gain
• Slow or fast heart rate
• Irregular menstrual cycle
• Intolerance to cold or hot temperatures
• Dry or moist skin

If you have any of these symptoms, you must consult the healthcare provider and get tested for thyroid function tests. You must not take these symptoms lightly, as thyroid disease can lead to various complications.

How To Prepare For A Thyroid Function Test?

As such, there are no special instructions for getting a thyroid test. If there are any special instructions, your healthcare providers will guide you about them. However, before going for the test, make sure that you wear loose-fitting clothes, especially the sleeves so that the healthcare providers can withdraw blood from your arm with ease. If you wear tight sleeves, it might become uncomfortable or even painful to withdraw blood from your arm. 

Thyroid Function Test Procedure

To perform thyroid function tests, you will have to uncover your arm so that blood can be withdrawn from the vein. It is performed like any other blood test. The healthcare provider will store the blood in a vial or a test tube. You might feel little to no pain. Make sure to press the wound to prevent bleeding from the puncture site.

Thyroid Function Test Normal Range

Thyroid function test's normal ranges differ from age to age. Your healthcare provider will tell whether your thyroid tests are fine or not, considering your age and other health conditions you have.

What Are The Risks Of A Thyroid Function Test?

As such, there are no risks associated with a thyroid function test. However, you can have pain at the puncture site. It might be accompanied by a bruise sometimes. You can apply a cold compress at the site to lower pain and inflammation.

In rare cases, when blood is withdrawn, you might experience:

• Dizziness
• Excessive bleeding
• Infection at the puncture site

How Long Does It Take To Get The Result Of Thyroid Function Test?

Generally, it does not take too long for the thyroid results to come. It might take one to two days from blood withdrawal for the thyroid function test results to come.