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Thyroglobulin (Serum) with Confirmation

Published: August 9, 2026Updated: August 16, 2026

This blood test measures thyroglobulin, a protein produced by thyroid cells. It helps confirm whether thyroid cancer has returned after treatment or if thyroid tissue remains in the body.

Quick summary

["Thyroglobulin testing is critical for monitoring thyroid cancer treatment and recurrence."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
110119-5
Short code
Thyroglob Ab Msmt Ser
Synonyms
Thyroglob Ab Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order this test after thyroid cancer treatment to check for signs of cancer returning. It’s often used in patients who’ve had thyroid surgery, radioactive iodine therapy, or other treatments for thyroid cancer. Your doctor may also recommend it if you have symptoms like unexplained weight changes, fatigue, or changes in your thyroid function.

How the Test Works

A small blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s tested for thyroglobulin levels using an immunoassay method. If the test is positive, it suggests thyroid tissue may still be present, which could indicate cancer recurrence.

What to Expect Before the Test

No special preparation is needed for this test. You can eat and drink normally on the day of your appointment. If you’re on blood thinners or have a history of bleeding disorders, let your doctor know before the test.

What to Expect After the Test

You may feel slight discomfort or bruising at the injection site, but this usually goes away quickly. Avoid vigorous activity for a few hours after the test to prevent excessive bleeding.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Thyroglobulin Confirmation

Frequently asked questions

What does a high or low thyroglobulin level mean?
A high level of thyroglobulin often suggests thyroid cancer has returned or that some thyroid tissue remains after treatment. A low or undetectable level usually means the cancer has been successfully treated and no active thyroid tissue is present.
How often should I get this test?
Your doctor will determine how often you need this test based on your treatment history and overall health. Typically, it’s done every few months to a year after initial treatment to monitor for recurrence.
Can diet or medications affect thyroglobulin levels?
Some medications, especially those that affect thyroid function, may influence thyroglobulin levels. Certain foods or supplements can also have indirect effects, but your doctor will consider these factors when interpreting your results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy