What Do Elevated Thyroid Antibodies and Normal TSH Mean?

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If your doctor has told you that you have elevated "thyroid antibodies," but at the same time, you have a normal thyroid stimulating hormone (TSH) level, what does that specifically mean for you?

Hashimoto's Thyroiditis

This particular combination of elevated thyroid antibodies and normal TSH could mean that you have undiagnosed Hashimoto's thyroiditis. Hashimoto's disease is an autoimmune disorder that occurs when your body produces thyroid peroxidase (TPO) antibodies that attack your thyroid gland.

Over time, the antibodies cause inflammation and eventually the thyroid gland, or portions of it, is destroyed, The result is hypothyroidism—a slowdown of your thyroid and reduction of its ability to produce hormone—as well as nodules, or the enlargement of the thyroid known as goiter.

With Hashimoto's disease, for a time before your thyroid gland is completely dysfunctional, you could have a normal TSH test result, along with the presence of elevated thyroid antibodies.

If your test results show elevated thyroid antibodies and a normal TSH level, it likely means your thyroid is failing over time—but at this point, it has not failed enough to warrant treatment, according to many conventional practitioners. Like many people with developing Hashimoto's disease, you may have some noticeable symptoms right now.  Eventually, as the disease progresses, you are likely to experience new symptoms, or your current symptoms may worsen, as the thyroid gland becomes increasingly less capable of functioning.

The Controversy Over Treating Thyroid Antibodies

Many conventional physicians and endocrinologists believe that elevated TPO antibodies alone are NOT enough reason to treat you with thyroid hormone replacement drugs. This is controversial, however, as there is evidence that the presence of thyroid antibodies alone can cause numerous symptoms.

Elevated thyroid antibodies have been shown to affect cholesterol levels, fertility, and pregnancy outcomes. A review published in Obstetrics and Gynecology noted "...evidence is accumulating that the odds of a miscarriage are more than tripled and the odds of preterm birth are doubled in the presence of thyroid autoantibodies."

There are, however, some endocrinologists, as well as holistic MDs, osteopaths and other practitioners who believe that the presence of thyroid antibodies alone is enough to warrant treatment with small amounts of thyroid hormone. If you've tested positive for antibodies, and have a TSH in the "normal range," but still don't feel well, you may wish to consult with a practitioner who has this philosophy.

The TSH Reference Range Controversy

The other issue is your TSH level itself. While at many labs, the "normal" or reference range is .5 to 5.5 (with over 5.5 being hypothyroid), some endocrinologists, and many integrative physicians and hormone experts, firmly believe that thyroid function is not optimized unless TSH is below 1.5.

 

Research evaluated the effectiveness of treating people who had normal TSH levels, but also had TPO antibodies show up in their test results. In the study, participants who received treatment with thyroid hormone replacement medication showed a reduction in their thyroid antibody levels, and reduction of inflammation that resulted in a reduced thyroid size. Patients in the study who did not receive treatment with thyroid medication during the 15-month term of the study showed an increase in thyroid inflammation.

The long term trajectory of your condition could be impacted by initial treatment. In the study mentioned above, patients who received thyroid hormone medication suffered less damage to their thyroid gland when evaluated 15 months after treatment.  If left untreated, the immune dysfunction associated with Hashimoto's disease continues to progress, and can permanent destroy your thyroid tissue. 

Thyroid Antibodies Should Not Be Ignored

If you haven't had your antibodies tested, and suspect you may be hypothyroid despite a "normal" TSH test result, read HELP! My TSH Is "Normal" But I Think I'm Hypothyroid for more ideas on how to proceed, how to define the "normal" range with your doctor, antibody testing, Free T3 testing, and drugs beyond T4-only therapy—and where to find a doctor to help. 

Sources:

Braverman, L, Cooper D. Werner & Ingbar's The Thyroid, 10th Edition. WLL/Wolters Kluwer; 2012.

Garber, J, Cobin, R, Gharib, H, et. al. "Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association." Endocrine Practice. Vol 18 No. 6 November/December 2012.

Kent, Athol. “Thyroid Antibodies Associated With Miscarriage and Preterm Birth.” Reviews in Obstetrics and Gynecology 4.3-4 (2011): 128–129. 

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