Low normal total T3 but good free T3?

[Knittergirl3]

I’ve never had a total T3 test before and I am confused with my results.

TT 10 years ago

50 year old female

Started Armour 90 mcgs

2 weeks on Armour

TSH .09

FT3 3.4 (2.5-4.3)

FT4 .9 (.8-1.7)

One month on 90 mcgs Armour

FT3 3.9

FT4 .8

Three months on 90 mcgs Armour

TSH .120

Total T3 83.0 ng/dL ( 60-180)

FT4 .8

Could someone help me interpret the total T3? 83 seems to be low but in my previous labs it was coming up nicely?

I was contemplating a dose increase because my anxiety and insomnia are showing up occasionally but I’m unsure.

Thanks so much for any advice you can share.

Kathy

[diogenes Remembering]

There isn't a hard and fast relationship between total and free T3 (or between total T4 and free T4 for that matter). If you have a lower amount of the proteins that carry total T3 and T4 around in your blood, which the tissues sample through FT3 and FT4 as the proteins pass by, then the T3 and T4 reservoir is smaller. But this smaller reservoir can still give a correct FT3 and FT4. Some people have large amounts of carrying proteins with big T3 and T4 reservoirs, but they can still give the same FT3 and FT4.

[Knittergirl3 in reply to diogenes]

Thanks for the explanation I really appreciate it. So I shouldn’t base a dose increase on my Total T3 being low?

I feel the pressure to increase my Armour dose. No thyroid and only on 90 mcgs of Armour seems low to many’s standards. And I do have some lingering symptoms that flare up.

[diogenes Remembering in reply to Knittergirl3]

Rely on FT3 not total T3.