free t3 LC/MS-MS

[Joey786]

Has anyone tested thyroid hormones using LC/MS-MS instead of immunoassay testing? I read a study about the inaccuracy of the immunoassay when testing levels in the lower part of the range especially for free t3. My most recent free t3 level by immunoassay was 2.5pg/ml range 2.0-4.4pg/ml. With a free t3 level of 2.5pg/ml I know I should be taking thyroid medication. I just want to know if anyone has used the LCMS-MS test and gotten different results than the immunoassay? The study mentions the immunoassay does not exclude thyroid binding proteins from the hormone measured so levels may be falsely higher than they really are.

How reliable are free thyroid and total T3 hormone assays?

 

[Vince Carter]

I think that the lab range

2.0-4.4pg/ml

is what we see the most of as we tend to advise that 3.9 and above is sufficient. I've not seen the difference in the two tests applied to Thyroid on this forum like we do with Estrogen testing.

 

[Joey786]

Thanks for the reply Vince Carter. On my next blood test I’m going to try the lcms. I’ll share my results with the forum.