I recently had two blood test due to numbness and tingling. One came back as borderline b12, the other low - 182. I understand the b12 range can vary according to postcode, how can I find out what they are for my area (north Herts).

Dr suggested the Pill was the reason for the borderline/ low results and sent me away to take a vitamin tablet with a b12 complex. But I'm not completely happy with this and not sure how to proceed. Should I come off Pill and ask for a another test? Ask to be referred to Haematologist? Ask for another type of test - IFAB? I have other symptoms including brain fog, Vertiligo (diagnosed in 2012, nothing said at time about b12), poor sleep and poor digestion.

Guidance most appreciated

3 Replies

  • Hi Confused-com you need to look at the <from - to> ranges on the test results to make a comparison.

    Was you Folate tested at the same time?

    Certain contraceptive pills can affect B12 levels.

    I'm not medically qualified but there are others on here who will be able to give you good advice.

  • The ranges depend on the kit and how the normal range is being defined by the lab performing the test. As clivealive says you need to look at the ranges on the test results.

    Unfortunately serum B12 isn't a gold standard test as it measures the amounts of B12 in your blood but doesn't actually say anything about what is happening at the cell level. People vary a lot in how much B12 which means that setting ranges is very difficult. It would appear that generally the normal range on its own means that 25% of B12 deficient people are going to be missed (and 5-10% who aren't deficient are going to be identified as being deficient). However, most GPs aren't aware of this limitation.

    The variation between your two tests isn't particularly significant and is probably within the normal variation for the test.

    The pill (progesterone related) is a potential drug interaction that can cause a B12 deficiency so it is worth testing it out as a factor, but would suggest that you continue to take the B12 tablets that your GP has given you and see what that does. If there isn't any improvement in a couple of weeks then go back to your GP and ask to discuss again

    Unfortunately like most tests related to B12 IFAB is a problematic test as it is prone to false negatives so a negative result doesn't rule out PA - but there are also other absorption problems that can result in a B12 deficiency - including coeliacs so might be worth following up on that as well.

  • I would advice you to keep reading this excellent site and you will gain so much info and insight. It really is a huge source of information and much more so than the doctors tell you. Also if you supplement with b12 the next results will be skewed.

    Good luck.

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