Thyroid UK
87,584 members102,289 posts

Optimal blood results?

Hi all, just wanting to pick more knowledgeable brains than mine. First, a bit of history.

Hypothyroid for 40+ years and eventually diagnosed via Dr Peatfield and on NDT, but this became too expensive.

Moved to Levo 30 years ago (by then NHS was willing to acknowledge the problem as my bloods had entered their concern ranges.)

Perfectly happy then about 3 years ago I developed A Fib following a return of symptoms and Dr P suggested that I was unable to convert T4 due to RT3 and recommended I try T3. My GP at the time was happy with that and I've been on it ever since. Find it easy to manage and very helpful with occasional A Fib as I can adjust dosage easily if necessary.

Had an issue some months ago when the practice said they would no longer prescribe but CCG intervened, said I ought to see an endo and endo said I should be on it so I'm back on it.

Lately I have had a full blood screen because I've had some odd symptoms - some loss of feeling in left toe, slight numbness/pins and needles/sort of "pre-cramp" feelings in both calves, plus pins and needles around my lips. This last as eased slightly on a marginally higher dose but the leg issues persist.

This time I asked for B12 and ferritin too and these are the results with ranges (others available if needed):

serum ferritin (BSC) 62 ng/mL (10.00 -300.00)

B12 532 pg/mL (200-900)

serum calcium 2.33 mmmol/L (2.20-2.60)

I think what I'm asking is what the impact of these levels might be and what I ought to try to do about them (if anything). I am woefully uninformed about this kind of thing, so hoping one of you knows more! Surgery says all is normal and I have a consult coming up to discuss what next since symptoms persist - though they vary in intensity from day to day.

Over to you!

6 Replies

Did you also get folate result? And vitamin D?

Vitamin B12 looks too low. We seem to need it nearer 1000.


Thank you for the reply. Serum foliate was 12.7 ng/ml (3-12) but Vit D wasn't done. He did the usual plus the ferritin and B12 at my request.

What difference does ferritin make? I have no idea. The level you mention is 3 times the high end of range so I'm going to need information on that if he's to help!


SlowDragon mentioned the Vitamin B12 should be nearer to 1000, NOT the ferritin.

Ferritin wasn't mentioned in her post at all!

1 like

My error. Trying to do too many things at once! Thanks for pointing it out!!


serum ferritin (BSC) 62 ng/mL (10.00 -300.00)

Mid-range for your ferritin would be 155 ng/mL based on the reference range you give. Your result is less than a fifth of the way through the range - 17.9% of the way through the range to be a little more precise.

You really need to increase your level to mid-range if you can.

Ferritin is a measure of your iron stores, so to raise it you need to supplement with iron.

Low iron can cause all sorts of fatigue symptoms, and breathlessness is also very common. Low iron can reduce conversion of T4 to T3. See the symptoms listed here

There are lots of different kinds of iron supplements. One of the ones that doctors prescribe is ferrous fumarate.

Assuming you live in the UK :

Go to pharmacy and ask for :

Ferrous Fumarate 210mg, in a box of 84

(You can buy online as well, although I've never done this.)

It is up to the pharmacist's discretion whether or not they agree to sell it. They could insist on a prescription. Boots pharmacists often do this. I've successfully bought ferrous fumarate in Lloyds and Tesco pharmacies without a prescription.

Buy a single box to start with. A lot of people find it hard to tolerate iron supplements so you shouldn't buy too many to begin with. If you don't tolerate the ferrous fumarate write a new question and ask for other suggestions - other kinds of iron supplement tend to contain less iron and cost more money.

Each iron pill should be taken with 500mg - 1000mg vitamin C to aid absorption and to mitigate the constipation that is often a side-effect of taking iron supplements.

Take one a day for a few days then increase to two per day (not at the same time). The maximum dose is one tablet, three times per day.

Iron is poisonous in overdose, so regular testing is absolutely essential. People differ in their ability to absorb iron, so until you know how well you absorb it you should err on the side of caution and test frequently. I would suggest waiting no more than 6 - 8 weeks for your first test once you start supplementing.

Please note that iron supplements and thyroid meds must be taken at least 4 hours apart because iron supplements reduce the absorption of thyroid meds.

1 like

Thank you, humanbean, for this detailed reply. I will discuss this with my GP and see where we go from there.


You may also like...