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Wanted to share something I found out today that literally shocked me. I visited a new Endo with my daughter. It was her appt.
Both of us became "hyper" around the same time. Fast forward, this nice new doc asked if she was taking supplements. We ran off the list of what we take and when we got to Biotin he stopped us. He told us, their lab uses a form of Biotin to test TSH levels. If there is Biotin in your system, you can very likely get a False Zero TSH. But all labs are different. He explained the method our lab uses and it's more than likely the Biotin supplement causing her low TSH reading. Mine, we're not sure but he was surprised I was put on Methimazole without being tested without Biotin in my system for at least a month.
You can also get a false TRAB reading. (below)
I confirmed this on the Internet and found out different labs use somewhat different methods to test thyroid but to be sure, Biotin can affect TSH and sometimes T4. It can flip flop according to your lab. I'll paste some below I found on Endocrine News.
This could explain why I had the bad lethargy and depression on higher doses of Methimazole and finally tapered to 2.5 mg. I might not even need it.
Many patients are taking megadoses of biotin that can cause falsely high and falsely low results in a variety of laboratory tests, including thyroid tests.
Patients are taking these supplements mainly to improve their hair, skin, and nails — and might not consider them medications to report on their list.
Biotin interference with lab tests could be causing misdiagnoses — and even mistreatment — in an unknown number of patients. [/pullout-wide]
Large amounts of biotin in a patient sample can interfere with this process. However, the effects can be confusing because, depending on the particular assay, biotin can skew the results to be either falsely high or falsely low. In the case of competitive immunoassays — usually used for low molecular weight targets (such as T4, T3, and cortisol) — biotin interference causes a falsely high result. In immunometric (sandwich) assays, it gives a falsely low result.
Other characteristics of the assay can also make a difference. For instance, a longer incubation time increases the opportunity for interference. Different assays for various analytes, even from the same manufacturer, can therefore vary in their susceptibility to biotin interference.
At the laboratory Mariash uses, the free T4 and total T3 assays use a biotin-streptavidin fluorescent detection system, so biotin can cause falsely elevated results, but the TSH and total T4 assays are not affected. In contrast, at Greenlee’s lab, biotin can lead to falsely low TSH results, but free T3 and free T4 tests are not affected. Biotin can also cause her lab’s assay for thyrotropin receptor antibodies (TRAb) to be falsely positive, which could lead to a misdiagnosis of Graves disease.So I'm not taking any Biotin and cutting out some of my other supplements and Methimazole until my next blood test on 10/19 and see what my readings are.
It's worth speaking to your doctor about this, especially if you're not symptomatic like my daughter and myself. I might be slightly hyper due to my nodule, or it could be a combination of nodule and Biotin making TSH even lower.
I wish I could post the source because there is a lot of interesting info on this issue of January 2016: Thyroid Month. Beware of Biotin.
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