Can you have Hashimotos and test negative?
What Are Antithyroid Antibodies?
The thyroid is a gland at the bottom of your neck, just below your Adam’s apple. It makes hormones that help your body use energy, stay warm, and keep the brain, heart, muscles, and other organs working.
Antibodies are made by your immune system to protect your body from bacteria and viruses. When harmful things invade your body, antibodies destroy them. Antithyroid antibodies, for example, attack your thyroid gland by mistake. That can lead to too much or not enough thyroid hormones.
Effect on Health
Antithyroid antibodies target specific parts of the thyroid gland, including:
Thyroid peroxidase (TPO). TPO is an enzyme that plays an important role in making thyroid hormones.
Thyroglobulin (Tg). This substance also helps your body make thyroid hormones.
Thyroid stimulating hormone (TSH) receptor. TSH sticks to the receptor on thyroid cells, which causes the gland to make and release thyroid hormone into the blood.
The antibodies can damage the gland, make it swell, and affect how it works. This can lead to medical conditions like:
Hashimoto’s disease. This is the most common form of underactive thyroid, called hypothyroidism. When the thyroid gland is inflamed, it can’t make hormones as well as it normally does. Over many years, the thyroid becomes damaged. This leads to a drop in thyroid hormone levels in your blood. When the levels get too low, your body’s cells can’t get enough thyroid hormone and they can’t work as they should.
Signs of Hashimoto’s disease include:
- Feeling very tired or sluggish
- Being very sensitive to cold
- Weight gain
- Body or joint pain
- Feeling depressed
Graves’ disease. This happens when antibodies cause the cells in your gland to work overtime. An overactive thyroid, or hyperthyroidism, makes and releases too much thyroid hormones into your blood. When that happens, all your body functions tend to speed up.
Symptoms of Graves’ disease include:
- Anxiety or irritability
- Bulging eyes
- Sensitivity to heat
- Unexplained weight loss
- Shaking hands or fingers
- Tiredness
- Fast or irregular heartbeat
Test
After doing routine blood testing to check for hormone levels, your doctor may order an antibodies test to look for Hashimoto’s disease or Graves’ disease. An antibody test can help your doctor figure out if your immune system is attacking the thyroid gland, or if something else might be the cause. They might also order antibodies testing for:
Goiter. This is an enlarged thyroid gland. It can be caused by several conditions, including Hashimoto’s disease or Graves’ disease.
Autoimmune disease, like lupus or rheumatoid arthritis. These and other disorders may raise your chance of having a thyroid problem.
How It’s Done
Your doctor or a lab technician will take a sample of your blood to measure how many antithyroid antibodies are in it.
Some medicines can affect test results. Tell your doctor if you take any drugs, herbs, vitamins, and supplements. Being pregnant may also affect results, so let your doctor know if you’re expecting or think you may be.
Results
If the test finds no antibodies, it likely means your immune system is not the cause of your symptoms.
If your results show high levels of antibodies against thyroid peroxidase or thyroglobulin, you may have Hashimoto’s disease. If you have lots of antibodies against the thyroid stimulating hormone receptor, you may have Graves’ disease.
The higher your level of antibodies, the more likely that you have a thyroid disease caused by your immune system.
Show Sources
Mayo Clinic: “Thyroid Gland,” “Hashimoto’s Disease,” “Graves’ Disease,” “Goiter.”
American Thyroid Association: “What You Need to Know About the Thyroid,” “Thyroid Function Tests,” “Hashimoto’s Thyroiditis,” “Hypothyroidism,” “Graves’ Disease,” “Hyperthyroidism.”
American Association of Clinical Chemistry: “Thyroid Antibodies.”
University of Rochester Medical Center: “Thyroid Antibody.”
Antithyroglobulin antibody test
to a protein called thyroglobulin. This protein is found in thyroid cells.
Alternative Names
Thyroglobulin antibody; Thyroiditis — thyroglobulin antibody; Hypothyroidism — thyroglobulin antibody; Thyroiditis — thyroglobulin antibody; Graves disease — thyroglobulin antibody; Underactive thyroid — thyroglobulin antibody
How the Test is Performed
How to Prepare for the Test
You may be told not to eat or drink anything for several hours (usually overnight). Your health care provider may monitor you or tell you to stop taking certain medicines for a short time before the test because they may affect the test results. DO NOT stop taking any medicine without first talking to your provider.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
This test helps detect possible thyroid problems.
Antithyroglobulin antibodies can be a sign of thyroid gland damage caused by the immune system. They may be measured if
Measuring thyroglobulin antibody levels after treatment for thyroid cancer can help your provider decide what the best test is to monitor you for a recurrence of the cancer.
Normal Results
A negative test result is a normal result. It means no antibodies to thyroglobulin are found in your blood.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
A positive test means antithyroglobulin antibodies are found in your blood. They may be present with:
Systemic lupus erythematosus
Type 1 diabetes
Pregnant women and relatives of those with autoimmune thyroiditis may also test positive for these antibodies.
If you have a positive test for antithyroglobulin antibodies, this may make it harder to measure your thyroglobulin level accurately. Thyroglobulin level is an important blood test to determine risk that thyroid cancer will recur.
Risks
There is little risk involved with having your blood taken.Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood buildup under the skin)
- Infection (a slight risk any time the skin is broken)
References
Guber HA, Farag AF. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 24.
Salvatore D, Davies TF, Schlumberger MJ, Hay ID, Larsen PR. Thyroid physiology and diagnostic evaluation of patients with thyroid disorders. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016:chap 11.
Weiss RE, Refetoff S. Thyroid function testing. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 78.
Review Date: 02/22/2018
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. Copyright ©2019 A.D.A.M., Inc., as modified by University of California San Francisco. Any duplication or distribution of the information contained herein is strictly prohibited.
Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Health. Please discuss with your doctor any questions or concerns you may have.
