Suppressed TSH when on Thyroid Treatment Does Not Mean the Patient is Hyperthyroid

There is a new research paper out which again shows that the current use of TSH when thyroid patients are on thyroid hormones is flawed.

The paper shows those patients who have had total thyroidectomy are very likely to require a suppressed TSH in order to be able to give them enough T4 hormone replacement to correct their symptoms.  In these athyreotic (no thyroid) cases, it is clear from the study that a suppressed TSH does not mean the patients are hyperthyroid. In fact, it is often necessary to have a suppressed TSH in order to provide enough T4 medication to get a sufficiently high FT3 level that the patient feels well.

It is also clear from the research that athyreotics are just one of end the spectrum to those with reduced thyroid hormone production. It is a spectrum and it should be clear that simply having a very low or suppressed TSH cannot mean automatically that a thyroid patient receiving thyroid treatment is hyperthyroid.

One of the big take aways from this is that endocrinologists and doctors should stop assuming that every time a thyroid patient has very low or near zero (suppressed) TSH on thyroid treatment that this means the person is hyperthyroid.

If someone is NOT on thyroid treatment but has a suppressed TSH then this situation is utterly different to when a patient is under treatment.

It is not a problem at all for a thyroid patient who is receiving thyroid hormone treatment to have a suppressed TSH, as long as they don't have actual hyperthyroid symptoms (or elevated FT3).

The practice of automatically reducing thyroid medication due to suppressed TSH is quite wrong. That is just a numbers game and makes no allowance for either the research or the clinical presentation of the patient.

This practice of never allowing a suppressed TSH when on thyroid medication is making the flawed assumption that you can treat thyroid patients receiving thyroid medication as if they are on no medication at all and hyperthyroid. It quite wrong.

For those on thyroid treatment the clinical presentation must be paramount and the use of simplistic thyroid labs must come secondary.

Here are the details on the paper: 

Heterogenous Biochemical Expression of Hormone Activity in Subclinical/
Overt Hyperthyroidism and Exogenous Thyrotoxicosis
Rudolf Hoermann, John E.M. Midgley, Rolf Larisch, Johannes W. Dietrich
PII: S2214-6237(19)30152-8

Here is the link: DOI: https://doi.org/10.1016/j.jcte.2020.100219

Reference: JCTE 100219

Many thanks to John Midgley for letting me know about the paper.

Best wishes,

Paul