24hr Urine vs Serum Test

[QUE6T-33]

Tests taken on same day. Comparatively, there's less serum FT3 than T3 in urine.

what is likely to mean?

[PinkNinja]

What thyroid meds are you taking, if any? Are you hypo or hyper?

If you are hypo and taking T3 it could be that you are taking a little too much (this is conjecture on my part) or that you are not using as much of it at the cellular level as you could be (again, a guess).

If you are still feeling hypo then perhaps there is a reverse T3 problem that means you are not using the T3 in your system very well. It could perhaps also be that low iron means that you are not using the T3 very well.

I really don't know though, and these are guesses. If you have your actual results with reference ranges someone else might be able to help

Carolyn x

[QUE6T-33 in reply to PinkNinja]

Hi Carolyn, Interesting. Share with me your train of thought that more FT3 in Urine than Serum level FT3 could suggest not utilizing FT3 at cellular level? I think your right actually (good guess), but like to understand how you arrived at.

NOTE Iron good. Hypo State. Few months on Armour. After 1st month on 1/2 grain bloods real good, RT3 had risen tho' (your guess right again) & Cortisol Serum had elevated. So I reduced Armour to 1/4 grain for 4 weeks then had another Serum test plus Urine. Serum FT3 had significantly reduced to below range. Urine was low but not as much. (Last Armour taken 24hrs prior test.)

Dr. requested both Serum and Urine to assess uptake.

Penny

[PinkNinja in reply to QUE6T-33]

It was just a guess as I don't really understand enough about this. I'm guessing that, as your doctor wanted both tests to assess uptake, that it might mean uptake isn't as good as it could be. As Rod says below, and I mentioned above, it would be helpful to know the exact results.

My reasoning, which may well be wrong, is that if you have higher than normal T3 levels in your urine, it suggests you are either getting too much T3 or you are not using it for some reason. If it is low, it suggests hypothyroidism. The blood level would help to confirm whether your blood levels are normal or not. I would imagine the results might also vary for other reasons, perhaps kidney function, but I don't know this.

If you have the actual results, please post them. It might help people to give a better answer

Your doctor will probably be able to explain to you what the results mean too.

[helvella Administrator Thyroid UK]

I really, really do not understand what you mean by this Comparatively, there's less serum FT3 than T3 in urine.

It might make more sense to me if you posted the actual results and the reference ranges.

Rod

[spring13]

Why on earth did you do a 24hr urine collection for T3 when there is a perfectly good blood test?

[QUE6T-33 in reply to spring13]

Both carried out at Drs. request. Dr. P. has requested in past also.

[spring13 in reply to QUE6T-33]

NHS or private?