Fluctuating T4

[Riya1980]

I went through Thyroid test 6 weeks back. My TSH, Free T3 were normal but Free T4 was low (0.83). I am on medication and taking Thyrox (half a tablet of 25 mg). I went through Thyroid test (TSH and T4 this time) again yesterday as prescribed by my doctor. Now, TSH is normal but T4 is high (14.1). Kindly help me in understanding what is the problem and the solution.

[Riya1980]

Sorry, that i dint respond your question. Actually, initially, i went to doc coz I was gaining weight and I suspect I am suffering from Thyroid. When I went through the test then it was detected that FT4 is low (0.83). Now, after 2 months, my FT4 is 1.24 which is in range.

[Riya1980]

Hi,

This is just to inform you that I have gone through my Thyroid test (TSH, FT4) and everything is normal.

Although, my doc asked me to continue my medicine till at least 2 years.

This is a good news so I wanted to share with you as well. :)

[Riya1980]

you are right. Until Thursday, I dint know that there is difference between FT4 and total T4. I just went to  get the T4 test done.

Now, I will go for FT4 and probably will get correct results.

Thank you for sparing time.

[goolarra]

I suspect one of two things is going on:

1) the 0.89 test is a free T4 test, and the 14.1 is a total T4 test (if the test isn't specifically identified as "free T4" or "FT4", it's total T4), or

2) the tests are both FT4, but were done at different labs which use different units so are not directly comparable.

This is why we have to post ranges (from our own lab report) along with results.  You will find the range on your lab report, usually in parentheses near the result.  If you don't have a printed copy, call your doctor and ask for range as well as result.  

[makani249]

I would be curious to know what is going on as well. I have a similar experience. My TSH and FT3 are with in the normal range. However, my FT4 is 0.8 and my Endo won't treat. Are you symptomatic at all with your T4 that low?