On Levothyroxine and being tested for Hashimoto's

[tylleedil]

I just started Levothyroxine 50 mcg 2 weeks ago.  the Dr. is going to re-check my levels in 6 weeks.  I have celiac disease and have always thought I had a thyroid problem.  Lots of the symptoms.  My question is.....He is going to test me for Hashimoto's which is an antibody blood test in 6 weeks.  Will taking the levothyroxine now (for 6 weeks) interfere witht the hashimoto's blood test?  I have read that 90% of Celiac Disease patitents also have Hashimoto's.  Both auto-immunne disorders.

[tylleedil]

Thanks so much for your response. I was worried that taking my levothyrixine would mess me up. I will continue taking it. I have searchdd and searched and could not find the answer, so decided to join and ask the question. So unlike me.

[goolarra]

Practically speaking, you can take your levo without worry that it will interfere with your antibody test.  Antibody results are frequently in the high hundreds, or even thousands, so it's extremely unlikely that even an 8% drop would turn a positive into a negative.  No thyroid meds lower antibodies significantly.  This is not like the antibody test for celiac, which can return a false negative if you are not eating gluten at the time of the test.  

I was tested after a year on levo, and I still returned a nice, positive result of TPOab 900+ and TGab 3,000+.  

Once we have one autoimmune disease, we are more likely to develop ANY other autoimmune disease than the general population is to get their first.  The connection is not only between celiac and Hashi's, but between either of those and type I diabetes, lupus, MS, pernicious anemia, etc.as well.  However, the percentage of celiacs with Hashi's is nowhere near 90%.  

As Red stated, of a very small sample of 184 patients with celiac, 21% were found to have positive Hashi's antibodies (not necessarily full blown thyroid disease).  TPOab and TGab can be somewhat elevated with other autoimmune conditions as well.  The big piece of data missing is how many of 184 people without celiac would test positive to thyroid antibodies. The connection between the two is only as strong as the difference between the two populations' (with and without Hashi's) results.

Anyway, take your meds and rest easy...      

[Red_Star]

A few studies have shown that levothyroxine can lower thyroid antibodies. One study mentions 8% drop in TPOAb in 3 months. This is not to say everyone will see this result however.  

The results of a 2007 Dutch study published in the World Journal of Gastroenterology confirmed a connection between Hashimotos Thyroiditis and celiac disease.

In this study, 104 patients with Hashimotos Thyroiditis were tested for celiac disease.  16 patients (15%) showed positive celiac serology and 5 patients clear villous atrophy were diagnosed with celiac disease.

In a separate test within this study, 184 patients with celiac disease were tested for thyroglobulin and thyroid peroxidase antibodies. 39 patients (21%) showed positive thyroid serology.

Serological markers for Hashimoto's thyroiditis:

Thyroid peroxidase antibodies (TPOAb): found in 90 - 95% of cases
Thyroglobulin antibodies (TgAb): found in 55 - 90% of cases

In a small percentage of cases, thyroid antibodies are negative.