Thyroid UK
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What to look for and ask about in blood test results

I was diagnosed with b12 deficiency in May, had loading dose and have kept up with my 12 weekly injections. However, I am still experiencing pain mainly in hands but also in legs, back, feet, head, around my eyes etc. extreme fatigue. I have had treatment for carpal tunnel (injections into wrists) but they have been unsuccessful.

My GP have now done blood tests to check my thyroid, vit. D, ferratin and folates. Unfortunately I have no idea how to read the results when they come through and want to know, if I'm told everything's clear, how close to borderline I am or if they've carried out the right tests.

I'm not even sure if there are standard units etc. in the UK or if different labs report results differently.

I know that there is something wrong, my fatigue is ridiculous, I rarely leave the house other than to go to work and the lethargy makes me not even want to straighten my hair as my arms ache too much.

Hopefully someone who has been down this route too will be able to help.

Thanks in advance

6 Replies

HI - welcome to the forum. When your results come through ask for a print-out of them (available from receptionist) and post them on here, including the ranges in brackets, and there will be lots of people who can advise on your specific issues. But your symptoms do sound like classic hypothyroid.

Gillian xx

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Agree with startagaingirl. Expect the gatepost from Reception when you ask for results and the 'I'll have to ask the doctor' response. Nicely be firm and you'll get them, though you might have ask more than once😣.

Those on here with lots of experience will then help you once you post your results. Trust you instinct and best of luck 😊.


Have you checked your symptoms against the list of Neurological signs with B12 Deficiency ? If you have some - then the Protocol for treating is completely different. You need injections every other day for a couple of weeks and then twice a week until symptoms are resolved ....

The neurological signs come first in the above link - scroll down to find them. Also lots more information on B12 Deficiency which so often accompanies Low Thyroid ....


Paffette71 Ranges do differ from lab to lab, particularly thyroid tests. Vit D doesn't, ferritin and folate can. As a general guide for vitamins and minerals:

Vit D - is recommended to be 100-150nmol/L

B12 - very top of range, even 900-1000 (according to the PA Society)

Ferritin - should be half way through it's range, at least 70 for thyroid hormone (our own or replacement) to work properly. I've seen it said for females it should be 100-130.

Folate - should be at least half way through it's range. Sometimes there's not a range just >XX.

For thyroid tests, anywhere within the range and you will be told you are fine. If you are close to the top for TSH and close to the bottom for FT4 and FT3 and symptomatic then you are possibly heading towards hypothyroidism

TSH - For a diagnosis of hypothyroidism, generally doctors want to see a TSH of over 10. The range may be something like 0.2-4.2. Even if you are over range, doctors tend to wait until it rises to 10. Most people feel best at the lower end of the range.

FT4 - most people feel best at the upper end of the range.

FT3 - most people feel best at the upper end of the range.

If you have had antibodies tested then it will say something like TPO Abs XX (your result) and <34 (possible number) so if you are less than 34 it's negative.

Ask for a copy of your test results, you are entitled to them under the Data Protection Act 1998. You can always ask to see the screen and write them down, or ask the receptionist to tell you what they are and write them down. Always get the reference ranges.

Hopefully you had your blood drawn at the very earliest appointment of the day and fasted overnight. That would give the highest TSH and your best chance of a diagnosis.

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Thanks for your advice. When I was diagnosed with b12 deficiency I was 89 which I know is Worfully low, as my GP put it especially as I am only 45. Having read a few threads, I'm just worried about. Ring fobbed off. I know something isn't right and it's not just carpal tunnel.


it may be that you just aren't getting B12 maintenance shots as frequently as you need them - ask your GP if he will do MMA test/homocysteine - these are nasties that build up if your body doesn't have enough B12 at the cell level to recycle them into useful building blocks.

Would also recommend joining the PAS forum on HU if you aren't already a member


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