A question about B12 testing

I asked my GP today for a Vit D and B12 test, she agreed I could have a Vit D test but said my last blood count test would have shown if there was a B12 deficiency, as all the markers came back within range for blood counts this showed I could not have any B12 deficiency. Sorry if I have not explained this very well. What I need to know is if there is a separate test just for B12 or does it depend on something being out of sync?

17 Replies

  • There is a separate test for B12. If you doctor was considering that you don't have megaloblastic anemia, well that's super super low B12 and if your folate is okay, it will prevent megaloblastic anemia. You should have B12 tested separately.

  • Thks gabkad that's interesting.

  • Joyia, wot Gabkad said about FBC ruling out anaemia, but to see whether your B12 levels are low or optimal you need a separate B12 test. My endo told me good FBC meant my vitD, ferritin, B12 and folate were fine. When I tested a month later vitD was severely deficient, folate deficient, B12 low and ferritin very high.

  • What is FBC Clutter?

  • Sorry, Flower. It's Full Blood Count.

  • I had this last week too. I asked for blood test for D3 and B12 as my last blood test was Oct 14 and both were borderline then. He refused B12 and did D3 which has come back really low @ 27 (sorry cant remember range think it starts @ 30). He prescribed vit d. I will start b12 again myself. Oh yes and my TSH was 5.7 so still high but note on blood test result says check again in 3 years!!

  • Hi flossyjoolz, your D levels were very similar to mine, I was given a minute 800iu, can I ask what your Doctor prescribed out of interest?

    When my symptoms changed I asked for a thyroid panel, was told we review once a year, so even that's a problem if things aren't right. He did reluctantly still do them, upon my insistence! When will they learn anything, but happy to give you anti- depressants at a drop of a hat. My sister is a pharmacist and she says doctors hand out those like sweets. Hard to believe the fight we have to get the right meds as good folk on this forum keep sharing.

  • Antidepressants of a tricyclic type are not recommend with thyroxine. check your patient information leaflet

  • Hi Sh65 I was prescribed 400iu vit D once a day and given a leaflet about spending time in the sun which is ok if we have some! Its true about anti depressants and this has happened to me several times. In fact the Rheumy who just discharged me to GP care said in her letter to him that my symptoms are all down to depression. How wrong she is. I have had depression in the past and I know I am not depressed at the moment. I am in lots of pain and am frustrated with not being able to do the things I used to but I am not depressed. Didnt stop the GP from prescribing Duloxetine. He says it is for the fibromyalgia I also have but im not sure so not taking them. They just will not listen to us regarding thyroid because the big pharma is not interested as not enough profit.

  • Your D3 is so low and you need at least 5000IU's daily or even loading doses in the beginning.... remember it is fat soluble so eat with good fats :-)


    Ranges are different to the UK so divide you result by 2.5 - bringing it to around 11.....

  • Hi Marz. thanks for the info. I didnt know that about vit D being fat soluble so will make sure I take it with the right food. My local NHS trust labs have just lowered the lower end range of vit d to 30 from 50 so it makes it looks like less people will be found below range when they are really lower than they should be. I noticed they have done that to a lot of the blood test ranges lately. Either that or the lab makes a note saying correct for this patient! Gentle hugs Joolz.x

  • ...sometimes the D capsules contain fat - so check the label :-)

  • My GP refuses to test ferritin or B12 as my blood count looked 'normal'.

    I paid to have ferritin and B12 tested with Blue Horizon, don't know if that's an option for you.

    I now supplement both.

  • Potnoodle it seems that GP's do use the blood count test then to decide if you are B12 deficient or not even if it is not tested individually, thks for your reply.

  • Hi Joyia, unless your doctor saw a B12 serum test as part of the panel she cannot say with any authority that you do not have a B12 deficiency. What she SEEMS to be doing here is making an assumption that because your blood count didn't show the signs of pernicious anaemia you therefore don't have a B12 problem. This just isn't true. You can have a B12 deficiency without having pernicious anaemia. You need to ask for a copy of the blood test, and unless you see a serum B12 test on it, then the test hasn't been done and you need to request one.

  • This idea that a Full Blood Count is all that is needed to show up B12 deficiency seems to have arisen an awful lot more since doctors needed to save money. This is all part of the privatisation of the NHS via the back door, in my opinion. If you don't get what you want from the NHS (and fewer and fewer of us are going to) your choices are to suffer, or to pay privately.

  • Thanks everybody for your interesting responses. As most of my surgeries GP's have now retired we have a new influx and it is hit and miss who you see, the Doctor last week was a very forceful lady and when I questioned B12 testing she raised her game and her voice; yes Chancery it would be great to have a separate B12 test but asking for one in the current climate and attitude seems an impossible task. Once again we are left with private testing and costs involved or go without.

    Whilst at my appointment I also asked for hydrotherapy treatment at my local hospital as I know people who have felt the benefits for their painful joints which I have, once again the response from my Doctor was one of reticence, "I will have to discuss this with the Practice Manager" she said, leading one to be convinced it is all about funding never mind the pain you are in. I was given a script for volperol only to find it cannot be used by anybody with an allergy to aspirin when I read the leaflet; next appointment I mentioned this faux pas as I have allergies and again a forceful response that only if you ingest aspirin do they have concerns, rubbing in cream is ok!! I ask you what is their reasoning as the skin is a living organ and what goes on it affects the whole system. The other suggestion for pain was paracetomol which I wont take either, much rather go down alternative route such as hydrotherapy, am waiting with bated breath for agreement or not. When I suggested a connection with the thyroid and painful joints this was met with glazed eyes and a quick come back suggestion that it was probably arthritis.

    Apologies for the rant, it is all so frustrating, how nice to be here with those who really understand though, much appreciation....

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