First FT3 result

[Tabitha6]

Hello everyone

I have recently had my first FT3 blood result and would be very grateful for any comments.

FT4. 25.32 pmol/L (12.0-22.0)

FT3. 5.1. pmol/L (3.1-6.8)

TSH. 0.022. mU/L (0.270-4.200)

[RedApple Administrator]

Tabitha6, What time was the blood drawn for this test, and when did you take your dose of levothyroxine prior to this blood draw? These things can have a bearing on how your resuts are interpreted

[Tabitha6 in reply to RedApple]

Thank you for replying. Blood was taken around 10am - first app I could get - 26 hours after last 100 levo.

[RedApple Administrator in reply to Tabitha6]

TSH is well below range, FT4 is well over range, which suggests you are probably over-medicated (i.e. on too high a dose). So if you are feeling unwell, I suggest reducing dose to 75mcg and see how that goes, with a follow up blood test after 4-6 weeks.

[RedApple Administrator in reply to RedApple]

FT3 is looking good, but make sure your follow up blood test also includes FT3 so that you can compare with this one.

[Tabitha6 in reply to RedApple]

Thank you RedApple, I will do. I’m feeling ok at moment apart from a “heavy” head, but was surprised at the FT4 figure myself. Oncologist keeps me high as had thyroidectomy due to thyroid cancer. Even so, 25 higher than normal. Thanks again for advice.

[RedApple Administrator in reply to Tabitha6]

Even though oncologist wants to keep you high, this looks a little too high. Maybe try 75mcg and 100mcg on alternate days to see if it helps your heavy head.

[Tabitha6 in reply to RedApple]

Good idea, thanks again.

[SlowDragon Administrator]

See you were severely vitamin D deficient and currently on high dose vitamin D

You may need to retest again once vitamin D is sorted. Perhaps get reverse T3 tested if you remain on high FT4

[Tabitha6 in reply to SlowDragon]

Thank you SlowDragon. Can you explain about the reverse T3 - is that when the T3 is not going where it should??

[SlowDragon Administrator in reply to Tabitha6]

If taking/have high FT4 then, especially if there are adrenal/cortisol issues or vitamin issues some of that FT4 can get converted in to the wrong sort of T3, called reverse T3.

Some reverse T3 is normal, it's a fail safe system to stop too much T3. But if Reverse T3 is too high, it can prevent FT3 being used

NHS doesn't test for it

If reverse T3 is high, then to improve, need to reduce amount of T4 taken and add T3

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

 please email Dionne at

[e-mail]

Professor Toft recent article saying, T3 may be necessary for many. Note especially his comments on current treatment following thyroidectomy or RAI

rcpe.ac.uk/sites/default/fi...

Very important to have very good levels of vitamin D, folate, B12 and ferritin too

[Tabitha6 in reply to SlowDragon]

Thank you Slowdragon, very helpful as always. Kind regards.

[diogenes Remembering]

At a ratio of FT4/FT3 of 5/1, this indicates to me that, because your FT3 is mid-OK, you are someone on the right side of the edge of being a poor converter. In other words, to get an adequate FT3, you have to load the T4 dose which results in a higher FT4. It is this extra load of T4 you need to get a reasonble FT3 that is suppressing your TSH result below normal. Poor converters can take any amount of T4 without achieving reasonable FT3, but you seem to have done it.

[Tabitha6]

Thank you for replying Diogenes.

I am so glad I found this forum, everyone is so helpful and I am learning so much, meaning I have been able to get my oncologist to test for something other than T4 and TSH! He has also referred me to an endo to deal with vitamin deficiencies etc.

Kind regards.