T4 way out of range.

[Wildroary]

I am heading for conflict with the new endocrinologist who has told me that looking at my results over 9 years it's indicative of failing to take my medication regularly. He does not seem to accept that I never have missed a day taking my medication in 9 years. Taken at least one hour before food with a glass of water.

I had a partial thyroidectomy in December 2008 and a papillary cancer was found after surgery so thyroid suppression is the plan but the Levothyroxine medication has not managed this yet. The levothyroxine started at 300mg in 2009 2075mg in 2012 and now 250mg 2 months ago.

Most recent results are TSH 0.46 fT3 5.5

fT4 29.6 My fT4 has varied between 30 and highs just over 40 over a nine year period with T3 always just over high range.

Apart from trying to get endocrinologist to believe I am taking my medication regularly I feel there could be other issues needs to be raised i.e. T4 away out of range and failing to suppress TSH.

Any advice about addressing this situation would be welcomed.

I must add that I have good health and a steady weight but can eat everything in sight and put little weigh on so worry in case I am in overdrive or if any ill effects being on high dose levothyroxine long term. .....

Cheers

[redeyes2]

Hello, Just a thought, my endo told me biotin can make our bloodwork appear worse. I mention this because my hair was falling out and I started taking biotin and it took a year before endo figured out what was going on. I stopped taking it and am now much closer to the normal ranges. Good luck, I hope they find an answer for you.

[jimh111]

Your endocrinologist is being dogmatic and silly, not to say rude. There's a theory that patients who are non-compliant and just take their hormone in the days before a blood test present with high fT4 and non-suppressed TSH. This is a load of b*****ks. TSH responds rapidly to fT3 and fT4, it is the long half life of T4 that leads to a slow build up of fT4 and hence a slow response of TSH.

An fT3 of 5.5 shows that you are converting T4 to T3 so impaired conversion can probably be ruled out. Normally an fT4 of 29.6 with an fT3 of 5.5 would be associated with a very low TSH. They want to suppress TSH to prevent the reoccurranc of papilary cancer.

The most likely cause is assay error. Sometimes antibodies can interfere with a TSH immunoassay assay giving a false high result. So, at a minimum they should try a different assay, to rule out antibody interference. If this turns out to be the case your endocrinologist owes you an apology and needs to attend a course on thyroid disorders.

It's just possible you have impaired T4 to T3 conversion, perhaps from selenium deficiency, but this is unlikely. If assay interference is ruled out you could ask that they test your selenium levels.

It may be that you have a very minor pituitary problem that causes it to pump out TSH, they can check for pituitary antibodies (can't remember what they are called, it's not TRAb). Possibly there is some other reason your pituitary is over-producing TSH. In any event they need to find out why your TSH is not suppressed. It seems that when a doctor doesn't understand a disorder they blame the patient rather than admitting their own lack of knowledge.

[Wildroary in reply to jimh111]

Thanks for your information. My local Locum GP has now written a firm letter to the endocrinologist and I now await his response.

BTW my GP agrees with you comments.

[Wildroary in reply to jimh111]

Latest from endocrinologist is that he accepts I am taking my medication and tells me TSH aggressive suppression guidelines have changed and I am low risk of papillary cancer returning so suppression of TSH is no longer required.

I now have a further reduction of Levothyroxine to 225mg and now told vitamin D is low so now on a supplement.

I will be watching further blood results closely, as always.

It seems a long time for changes in guidelines to be implemented as I understand TSH suppression guidelines where made in 2014.

[Clutter]

Wildroary,

If you supplement biotin or a B Complex which has biotin in it and lab uses biotin in assays it can skew thyroid and other blood tests. If so, skip the supplements for a day or two prior to your blood tests and all should be well.

endo.confex.com/endo/2016en...

If you don't supplement biotin/B complex then your endo should consider whether you may have antibodies to T4 skewing the result. Heterophile antibodies to TSH can cause false high TSH results but the TSH result is usually very high around 60+ with normal FT4 and FT3. In either case using a different lab with different assay analysis should rule out antibodies interfering with either FT4 or TSH.

If assay interference by antibodies is ruled out then your endo should investigate whether your pituitary is functioning properly and rule out TSHoma which is a benign pituitary adenoma secreting TSH.

Your endo is entitled to ask whether you are compliant but should accept your word when you tell him you are. If you were non-compliant and walloped down a lot of Levothyroxine prior to a blood test one would expect to see TSH high in range, not 0.46, with FT4 high in range.

I would hazard a guess that 275mcg would suppress your TSH <0.1 but it would raise your FT4 and FT3.