Thyroid UK
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A while ago I posted that I was feeling breathless after doing very little, even just walking up the stairs and I asked for some advice. It was suggested that I get some blood tests done, including my FT3 and so I had a private blood test done through Blue Horizon. I am currently taking 125 mg of T4 and 40 mg of T3. These are my results:

TSH - 0.010 (0.270-4.200) It is suggested I increase my Levothyroxine which I have to 150mg

Free T4 - 12.84 (12-22)

Free T3 - 5.5 (3.1 - 6.8)

Vitamin B12 - 410 (191-663)

Folate (serum) 12.2 (4.6-18.7)

Ferritin 125.2 (13-150)

Vitamin D 79.3

Serum cortisol 25 - This was taken a year ago by my GP and marked as "normal". I saw an endo who confirmed it was "normal"

One thing picked up on this latest blood test is:

Transferrin saturation - 50.9 (15-45) and that apparently indicates an iron overload???

The advice is to have another blood test for this in 6 weeks time. Does anyone know about this?

Any advice or comments would be appreciated.

I also have Essential Thrombocythemia

5 Replies

There are several reasons why you might have high transferrin saturation. Take a look at this link, particularly the table at the bottom of the page :

Based on your Free T4 and Free T3 you could easily manage to increase your levothyroxine. Be aware though that your GP will have kittens when s/he sees your low TSH. Don't let him/her frighten you. Your Free T3 isn't over the range, so you aren't over-medicated. If you feel over-medicated on a higher dose, then just reduce your dose again.

Your B12 is too low. The Pernicious Anaemia Society recommends a level of 1000. In Japan a level lower than 500 is considered deficient. I know 1000 is over the range you've been given, but it isn't poisonous, you'll just pee out any excess. The range in the UK is outrageously low.

Folate is not bad, could be a little better.

Your ferritin is fine. Don't supplement to get it any higher, you don't need more.

Vitamin D - optimal is round about 100 for many people. If you decide to supplement, be aware that some people don't do well on vitamin D. If this applies to you then just stop supplementing - your level is not bad anyway. It is a good idea to take vitamin K2 with vitamin D supplements. Vitamin D raises calcium levels, and vitamin K2 directs that calcium to your bones, where you want it to go.

Sorry, can't help with the cortisol.


Do you have the results with ranges from a recent full blood count?

Haemoglobin level doesn't necessarily correspond with ferritin level so the figures are needed, as too much iron or too little iron plus your platelet issues could be causing the problem.


Thanks for your answer bluebug. I am no expert so not sure what you mean but would appreciate your input. The Haemoglobin result from the recent blood test is 130 (120-150)


I was just ruling out that your breathlessness wasn't due to iron deficiency or overload. Your haemoglobin level is bang in range like ferritin.

The high transferrin saturation can have a few causes.

It could be due to not having your hypothyroidism under the control as you want.

It could be due to not having your B12 high enough.

(Blood markers can go out of range if you have a chronic illness or are vitamin deficient. )

Or it could just be a one time random reading which is why Blue Horizon recommend repeating the test in 6 weeks. (6 weeks is the minimum time they recommend to do another full blood count if values are out of range.)

I would follow what humanbean says about upping doses and supplementing then after a few months retesting.


Thank you bluebug, all very helpful


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