I’ve had two recent tests for thyroid and I’m very surprised they have tested t3. Why would they suddenly start testing t3 ? I’m not complaining but I’m confused as to why they would do this.
My tsh was very low, buts it’s been low before and on these occasions t3 was not tested. I’m currently on levo only treatment
Mine seems to get tested automatically if my TSH is below range or at all suppressed. They also do FT4 which some labs don't. Probably a post code lottery kind of thing but maybe they have changed their policy?
Because my TSH is normally suppressed, as it has been for years, although the GP may only ask for TSH, my T4 and T3 are generally tested as well. Seems to be a "lab thing"..... they decide what they'll test rather than what the DR/Endo has requested.
Some guidelines for doctors (and that may vary in different areas of the world) do recommend T3 testing ONLY when TSH is suppressed. It could be that TSH being low or even below reference interval prompted this test because the doctor now had a valid "excuse" to do it.
GP only testing TSH now - no longer T3/T4 - concerned! 
Why won't my gp push labs to test t3?
HELP.. GP will not test t3. No thyroid. 
TSH T3 and T4 NHS Test results via GP
GP won’t prescribe t3 
