TSH, FT4, TT3 ratios

[miseree]

In the last couple years I have noticed an extreme difficulty concentrating and focusing. I started researching and discovered the list of symptoms for hypothyroid. I couldn't believe the number of additional symptoms that I had on that list. I scheduled a physical and asked for thyroid testing. According to my doctor everything is in the 'normal' range. I was extremely disappointed that wasn't the answer to my issues, however I am not ready to give up. Would anyone mind reviewing my test results and tell me if that completely rules out thyroid issues? I am also wondering about the feasibility of Low T3 syndrom or Wilson's temperature syndrome (average body temperature is about 97 throughout the day). Part of my confusion is that they measured free T4 and total T3. Any thoughts are appreciated.

     result lab low lab high units
tsh      1.64    0.4             4         uIU/L
FT4      1.1    0.2             6         ng/DL
Total T3  127    80            190 ng/dL

[goolarra]

Thanks for checking that.  Wow!  That's a very odd range.  You're right 0.8-1.8 (or something very close to that) is "typical".  I'll bet just about no one is hyper at your lab!  LOL

Either way, your FT4 is on the low side.  Using your lab's range, it's about 15% of range.  Using 0.8-1.8, it's 30% of range.  Midrange (50%) is the target for FT4.  FT3 is a little bit on the low side, too.  Since you're not on meds, neither of those bothers me a lot.  TSH, for what it's worth, looks good.  It all looks pretty good.

In order to determine if it could be Wilson's (RT3 dominance), yout have to test both RT3 and FT3 in the same blood draw to get the FT3:RT3 ratio.

Vitamin D deficiency and B-12 deficiency can both have symptoms very similar to hypo symptoms.  Have you tested those?

Also, have you had thyroid antibodies tested to see if you might have early stage Hashi's?  TPOab (thyroid peroxidase antobodies) and TGab (thyroglobulin antibodies) are the two markers for Hashi's.      

[miseree]

Thanks for commenting. My GP called today and actually suggested a testosterone check as well, so we'll see how that goes. Thanks.

[miseree]

goolarra. Thanks for the post. I also agreed that the T4 seemed odd as the typical range that I found online was 0.8 to 1.8. I did confirm that my lab's range is indeed 0.2 to 6.0.

[Gibbon1]

Short comment.  You should also have your testosterone and cortisol levels checked if you have not already.  Hypogonadism and adrenal insufficiency have symptoms that are similar to hypothyroid.

[goolarra]

Please verify the range on your FT4.  0.2-6.0 is a very unusual range.  Also, be sure it's coming from your own lab report as ranges vary lab to lab.

As you suggest, the doctor should have ordered FT3, not total T3.  TT3 is considered obsolete and of limited usefulness.  

[Red_Star]

I should add, that this type of lab testing can be, as stated on the article, "artifactual" which means an inaccurate result. So retesting would be recommended.

[Red_Star]

Normal TSH with raised free T4 is an unusual pattern.  I found an excellent website i can send you with more information but this is the listed table of causes:

Normal or raised TSH, raised free T4 or free T3...

Rare—with discordant free T4 versus free T3:

* Interfering antibodies to thyroid hormones (anti-TPO antibodies
usually also present)
* Familial dysalbuminaemic hyperthyroxinaemia
* Amiodarone

Rare—other:

* Intermittent T4 therapy or T4 overdose
* Resistance to thyroid hormone
* TSH secreting pituitary tumour (hyperthyroid)
* Acute psychiatric illness (first 1–3 weeks)