Test Results Advice Please

A friend who is definitely symptomatic but undiagnosed has a T4 of 13 and TSH of 1.15, which I find surprising. I thought with such low T4 she would have a higher TSH. Any thoughts please? Her T3 wasn't tested.

[jezebel69]

HI - Some people need their TSH to be under 1.0 into a negative reading before symptoms subside (with a T4 of around 20) T3 is seldom tested even if requested by the GP. The lab chooses not to- way too much power I think That leaves us with expensive private testing......

[Hidden in reply to jezebel69]

Thanks, yes I know. Was just curious about why someone with such a low T4 reading didn't have a higher TSH.

[Clutter in reply to Hidden]

Sue, Do you have the FT4 lab ref range? They vary across the country so 13 may not necessarily be low.

[Hidden in reply to Clutter]

Sorry, I should have included that. It's (12 - 22) so 13 is low.

S

[Clutter in reply to Hidden]

Sue, if FT4 drops below range but TSH doesn't rise your friend may be looking at secondary hypothyroidism which is a pituitary dysfunction resulting in insufficient TSH to produce thyroid hormone. Advise her to have another thyroid test in 3 months and if FT4 is low she should ask for FT3 to be tested too. TSH is a useless test in secondary hypothyroidism.

patient.co.uk/doctor/hypopi...

[Hidden in reply to Clutter]

Many thanks Clutter - that's helpful.

S

[Hidden]

Could be secondary hypothyroidism also known as central*.I have it and my TSH never rose above 6.5 despite having a FT4 and FT3 well below range.

Trsting by the TSH when the problem is pituitary is pointless. She must get her FT3 tested.

* sometimes referred to as central because it is not always clear as to whether it is a pituitary problem (secondary) or a tertiary problem (hypothalamus).

Treatment is the same ie. replacement thyroxine

But she should have other Pituitary hormones tested too to make sure that they are not affected as well.

[Hidden in reply to Hidden]

Thank you. I'm learning a lot here!

[Hidden]

T3 is the active hormone so we are missing the most important info. I suggest getting a private test than the half ****** Nhs test that doesnt tell us what we most need to know

[Hidden]

Thank you. I'll encourage her to do this.