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Thyroid UK
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Help in understanding bloods please, any help HUGELY appreciated :)

Hi Guys, I wonder if you can help me understand B12 and Ferritin bloods? I have been feeling all out of sorts for a while. I have an under active thyroid, i started on 75 about a year ago and am now up to 100 of levothyroxine. I cant work out if i am taking too much or too little at the moment and my doctor is absolutely not the best, but my bloods have come back all wonky and I wonder if any of you could give me any insight. My Serum ferritin has come back 361.6 when normal range is 14-186 and my B12 has come back 972 when normal ranges is 197-771 My TSH is 0.48 and my T4 17.9 so seems normal, ultimately just dont feel "right". Any help would be hugely hugely appreciated in reading / understanding these as quite worried. Thanks guys xxxxxxxx

3 Replies

Hello Chillidog, ferritin is way too high. Have you been supplementing iron? If you haven't been supplementing iron then you need to book an appointment to discuss with GP and if you have been suppplementing you need to stop immediately.

B12 is a little over range but your body excretes the B12 it can't store so if it were me I wouldn't worry about it but again check with the doc. As you say, TSH and T4 ok.


Thank you so much for ur help nanaedake x


could you check the ranges you have given for B12 - they aren't ones I recognise - and was it serum B12 test or active B12 test - would also help to have the units of measurement quoted as there are actually too different ranges.

Some people do respond to high levels of B12 in serum by shutting down the mechanism that allows B12 to pass from blood to cells leaving you with a functional B12 deficiency.

It is also possible that tests can go wrong and give false readings if things are very out of whack - though I would expect the lab to have noted that on the results is they felt that was what was going on.

Please note that the PAS forum has a lot of information on B12



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