# How to calculate optimal Ft3/Ft4 levels



## Im-the-mom (Sep 4, 2014)

Had my to 09/14. Am truly struggling with not having the right dosage after this long. Am on 150 mcg Levothyroxine. My last labs had my t4 at just over the upper range, to near the bottom of range and the just over 1.

I have fired 2 doctors. I am finally getting in to see the endo that I researched and believe is the doctor that is going to listen to me, pay attention to my symptoms and give my life back.

My question is how do I calculate the proper optimal value for t3/4 and ft3/4? Is it just the upper range times .75? I saw somewhere where they took the upper range minus the lower range, then did something else that I don't remember.

I have felt so bad for so long, and I can't wait to get in to see this doctor. I just hope I don't get in there and cry from sheer exhaustion and frustration!


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## Lovlkn (Dec 20, 2009)

T-4 or Total 4 is not the correct test. Free T-4 is.

Example FT-4 level is 1.42 (.82-1.77) 1.77-.82= .95 -:- 4= .2375 x 3= .7125 + .82 = 1.5325. This is 3/4 of range


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## Octavia (Aug 1, 2011)

How to calculate:

1. High end of range minus low end of range

2. Take the result of step 1 and multiply it by 0.75

3. Add the result of step 2 to the low end of your range, and you have the 75% of range mark.


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## Im-the-mom (Sep 4, 2014)

Thank you so much! I have become aware that total t4 is not what I need to know. That's why I've changed doctors. I asked my last doctor to add ft3 and ft4 to my last test, and they didn't.


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## Lovlkn (Dec 20, 2009)

http://www.healthonelabs.com/pub/tests/test/pid/167

$59.75 and probably 3-4 days and you will know where your FT-4 and FT-3 labs are.

This bundle has a few useless tests but it's the cheapest I've found that offers FT-4 and FT-3 along with TSH


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