Seronegative Hashimoto’s, (SN) also called seronegative autoimmune thyroiditis, is far less common than regular Hashimoto’s, which is “seropositive, or serum positive. It’s an autoimmune condition where neither of the standard antibodies tests for Hashimoto’s disease will show rising or high circulating antibodies. Those standard antibody tests are 1) anti-TPO (anti-peroxidase) and 2) TgAb (anti-thyroglobulin).

How does one discover they have Seronegative Hashimoto’s?

Since Seronegative Hashimoto’s (SN) disease1 will not usually show itself with standard antibodies tests, it will show itself via an ultrasound2 test. The ultrasound will show images of your thyroid gland via sound waves. It is entirely painless and considered very safe. An ultrasound is often done is a hospital or clinic setting as prescribed by one’s doctor. You might also hear the term sonography, which is the same as ultrasound.

Some with SN can also find themselves with hyper-like symptoms, plus a low TSH and high free T4 and free T3, similar to regular Hashimoto’s. There might also be nodules. There can also be a thyroid with bigger volume than normal.

This is an example of an ultrasound most know about on the belly, though for seronegative Hashimoto’s, the ultrasound would be on the neck area where the thyroid gland would be.

What is seen in the ultrasound thyroid image in someone with Seronegative Hashimoto’s?

The image produced by an ultrasound with show the same hypoechoic (dark patterns)3 on the thyroid gland as does regular Hashimoto’s.

What’s another potential clue before an ultrasound?

Some patients have observed that their antibodies test can be high in the normal range before they did an ultrasound to prove Seronegative Hashimoto’s. That is different than what most with regular Hashimoto’s see, i.e. above range, high antibodies.

Is Seronegative Hashimoto’s considered common?

No. You will see mention of as little as 5%, give or take, or higher, of those with Hashimoto’s. On the Stop the Thyroid Madness Facebook page, it does get mentioned by some as if it’s more than 5%.

Is Seronegative Hashimoto’s as aggressive as regular Hashimoto’s can be?

Most studies hypothesize that it’s less aggressive4. Their conclusion is based on the fact that most with SN have no goiter and less severe inflammation. Of course, there can be exceptions.

How to I treat Seronegative Hashimoto’s?

You treat “serum negative” Hashimoto’s the same way that “serum positive” Hashimoto’s is treated. And you will find informative, patient-to-patient information on treatment in the book Hashimoto’s: Taming the Beast <—-this page gives you details about it!


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