Thyroid UK
82,897 members97,935 posts


Can I get this straight - can my iron level or serum ferritin be determined by a 'normal' blood test? My gp centre allows me to book as many blood tests as I want but I'm only allowed the super basic one. Like, if I have a high RBC count, does that mean my ferritin is high?

If this doesn't figure then what do I say to the doctor to let me have my ferritin tested? They still don't believe I'm hypothyroid, lol :)


12 Replies

Urgh I didn't make that clear. I meant, I am allowed to order a basic blood test for myself, but only the doctors can order different ones for me...hope that makes sense.


Superparrot, what is the basic blood test you are allowed to order?

Ferritin and iron are specific tests. Ferritin is often ordered instead of a full iron panel. If Ferritin is deficient iron anaemia is likely and a full iron panel, serum iron, binding%, saturation% etc may be ordered.

Low RBC may indicate iron, B12 or folate anaemia but high RBC won't indicate what ferritin or iron levels are.


Thanks clutter, that makes sense. I think the basic one is ssomething like haemoglobin, white cell count, RBC, a few other really basic things that say "you've got blood in your blood" ;)

Maybe I could go and yell at them about anaemia, though I don't feel anaemic. Perhaps I could just order blood tests until I am, lol :)


Superparrot, thats a full blood count (FBC) see the labtests link I posted for a rundown of what's included.

1 like

Hi superparrot, You may find this page useful :

The table at the bottom might be particularly useful.


Thanks! Very useful!

1 like

for some stupid reason best known to NHS labs Ferritin is not part of the normal blood tests because they will not face the importance of it in Hypothyroid

The sheer process of becoming hypothyroid trashes any of the vitamins in the body inc




vit d3

vit b

vit C

the latter 2 often right into Beri Beri and scurvy

1 like

Eek! I definitely need more c's and b's. So do you mean that my results are always going to be weird until I am medicated properly...?

Thank you :)


If you are testing as "normal" on a Full Blood Count you could still be anaemic if you are female, (hard to tell, superparrot) because the ranges for women are not evidence based.

You may also be fine on an FBC, but have low serum ferritin. Ferritin is a measure of how much stored iron your blood has. If your stored iron is low (serum ferritin below 50) you may still be feeling tired and have iron deficiency symptoms like anxiety and palpitations. This is called iron depletion.

A serum ferritin test is relatively cheap for the NHS, and low serum ferritin is very common amongst menstruating girls and women in particular. If you tell your GP that you are feeling very tired and would they mind awfully just checking your serum ferritin, because you don't want to supplement iron if it isn't needed, s/he should agree.

If they look at the inside of your eyelilds and say that they are nice and pink and therefore your iron levels are fine, ask them in your most polite voice what the evidence base is that the conjunctiva test is a guide to serum ferritin levels - could you have links to the studies?

Because it ain't an evidence based test for anything other than ruling advanced anaemia out.

1 like

Excellent ideas and information, thank you! Yes, ima girl ;)

I did take iron for a long time, when I didn't know better, and I'm more worried I've overdosed than anything else. Who knew it could be so harmful to have too much of a good thing?!

We live and learn. Slowly!


The body doesn't absorb iron easily, and it also has a mechanism for shutting absorption down, so you're probably fine.

1 like

Thanks, that is reassuring :)


You may also like...