Blood test shows too high T3 but low T4. Very c... - Thyroid UK

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Blood test shows too high T3 but low T4. Very confused.

N1mble profile image

Please help me interpret my confusing results:-

Vitamin B12- 657 (197-771)

Folate(serum)- 14.4(>2.9)

Ferritin 407(13-150)

c Reactive protein-11.1(<5.0)


TSH <0.01(0.27-4.2)



25 OH VitaminD 190(50-200)

Thyroglobulin Antibody-11(0-115)

Thyroid Peroxidase Antibodies-18.3(0-34)

Reverse T3----insufficient sample to assay!

Please take into account that I have recently (3 weeks ago) finished a powerful course of steroid tablets over a 4 week period to treat an itchy rash which started on my lower leg and rapidly spread covering most of my body and causing swollen lower legs and subcutaneous inflammation in the legs. This was diagnosed as 'excema', has almost gone but has left me with reddened skin and slight swelling to my legs with mild itchiness which now looks very much like pretibial myxedema, a symptom of thyroid imbalance.

Prior to this infection my hypothyroidism was reasonably well controlled by self medication of 100mcg T4 plus 50mcg T3 daily. I am now less energetic and unable to walk more than 100m uphill without resting. I am 72.

I had my blood test at 10am., 22 hours after taking T4 and T3.

These latest results have really thrown me.

Please advise how I might address them.

Thank you.

5 Replies


FT4 is low because you are taking proportionally more T3 than Levothyroxine. You are overmedicated to have FT3 over range 22 hours after last T3 dose. I suggest you halve your T3 dose to 25mcg for a couple of weeks to speed up clearance of high FT3 and then increase to 37.5mcg T3. Retest 6-8 weeks after taking 37.5mcg to see whether FT3 is back within range.

B12 and folate are good.

Ferritin is high. If you are supplementing iron you should stop immediately. If you are not supplementing iron ferritin may be high due to infection or inflammation, perhaps related to the ezcema. Ditto CRP which is an inflammation marker.

VitD is high in range. Around 100 is optimal. If you are supplementing you can stop for a couple of months and then resume 1,000iu daily to maintain levels until April.

N1mble profile image
N1mble in reply to Clutter

Thank you Clutter for such a prompt and concise reply.


SlowDragon profile image

Your Ferritin level on this old post was EXTREMELY high

This needs retesting

Hemochromatosis, (iron overload) is more common in Hashimoto's


Rarely, certain diseases, like hemochromatosis, can deposit abnormal substances (iron, in the case of hemochromatosis) in your pituitary gland, causing central hypothyroidism, or less commonly, your thyroid gland, causing primary hypothyroidism.

N1mble profile image
N1mble in reply to SlowDragon

Thank you fir commenting on my old post. Very considerate of you.



SlowDragon profile image
SlowDragonAdministrator in reply to N1mble

If you weren't on iron supplements and not had ferritin retested, GP should do so

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