Tsh level

[Brumhoy68]

Stupid question is it possible that levothyroxine cannot lower your tsh to a normal range?

[jimh111]

Not really. In rare cases, usually severe selenium deficiency (and very rare genetic conditions) there can be impaired T4 to T3 conversion. Otherwise even if T4 to T3 conversion is not good levothyroxine will reduce TSH. Sometimes there is antibody interference with the assay which can give a false TSH result.

Just looked at your previous post and notice your fT4 is low which would explain an elevated TSH. They should increase your levothyroxine dose, 100 mcg is not that much, many patients need around 150 mcg. I would get onto the hospital and explain that the doctors you are seeing are not helpful, that you would like some expert care until your levels have settled down. If you get nowhere go and see your MP.

[SilverAvocado]

TSH stands for thyroid stimulating hormone. It is a chemical messenger made by the pituitary to signal the thyroid to make more hormone. When the thyroid hormone in the body is low, TSH will be high to show the body needs more.

The freeT4 and freeT3 tests measure how much thyroid hormone is available in your blood. When these numbers are low your TSH will be high.

Levothyroxine contains T4. If you keep taking it, and keep increasing the dose, eventually you will get to the point where your freeT4 rises and gets to a level that your body is happy with. This will slowly reduce your TSH.

There can be rare cases when the freeT4 is high in range or over, but freeT3 is very low, and the TSH is high in response to a low freeT3. I've never actually seen this in someone when they first try Levothyroxine. It seems to be something that can only happen after you've been on Levo for years. But I may be wrong about that.

The simplest strategy if your TSH doesn't seem to be reducing is to get new blood tests and adjust your dose every 6 weeks. Continue increasing Levothyroxine by 25mcg until the blood tests look good or symptoms resolve.

If your freeT4 gets to the top of the range and you still don't feel well, at that point there are other things to try. At the same time make sure vitamins are good, folate, ferritin, vit B12 and vit D. These help the thyroid hormone to work.

[Angel_of_the_North]

If you have certain types of antibodies (monoclonal?) you will tend to have false high TSH tests. That's one reason why you need to have actual thyroid hormones tested , not just TSH. Sometimes, if you thyroid hormones are high in range, but TSH is also high, getting a test done by a different lab which uses a different assay might give you a better reading.