Patient education: Thyroglobulin test (The Basics)

What is a thyroglobulin test? — 

This is a test to check the level of thyroglobulin in the blood.

Thyroglobulin is a protein made by the thyroid, which is a gland in the middle of the neck (figure 1). The body uses thyroglobulin to make 2 thyroid hormones: T4 and T3.

Your doctor might also order a thyroglobulin "antibody" test at the same time. This can help your doctor understand your test results. Thyroglobulin antibodies do not cause any symptoms. But if you have them, they can make your thyroglobulin test results unreliable.

Why might I get a thyroglobulin test? — 

Your doctor might order this test to:

●Learn if treatment for some kinds of thyroid cancer is working

●Watch to see if thyroid cancer comes back

●Help learn the cause of high levels of T4 or T3

How do I prepare for a thyroglobulin test? — 

You need to get a "blood draw." Your doctor or nurse will tell you where to go for this.

It might help to wear a short-sleeve shirt to your blood draw appointment. This makes it easier for the person drawing your blood to get to your arm.

What happens during a blood draw? — 

A needle is used to take a small amount of blood from your arm (figure 2). Collecting the blood only takes a few minutes. The blood is then tested in a lab.

Tell the person who takes your blood:

●If you take "blood thinner" medicines or have a bleeding problem – They will make sure your bleeding is under control before you leave.

●If you have a latex allergy – Some of the supplies used for blood draws might contain latex.

●If you have a preferred arm to use

Most of the time, getting blood taken does not cause problems. You might have a little soreness or bruising where the needle went in.

What do my results mean? — 

Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

If your thyroglobulin test shows any abnormal results, your doctor or nurse will talk to you about what to do next. They might need to do more tests to figure out the cause.

If you do have a health problem, your doctor will work with you to come up with a treatment plan.

More on this topic

Patient education: Thyroid cancer (The Basics)
Patient education: Thyroid nodules (The Basics)
Patient education: Thyroidectomy (The Basics)
Patient education: Hypothyroidism (underactive thyroid) (The Basics)
Patient education: Hyperthyroidism (overactive thyroid) (The Basics)
Patient education: Free T4 test (The Basics)
Patient education: T3 tests (The Basics)

Patient education: Thyroid nodules (Beyond the Basics)
Patient education: Hypothyroidism (underactive thyroid) (Beyond the Basics)
Patient education: Hyperthyroidism (overactive thyroid) (Beyond the Basics)