Wee bit confused

[ajw1205]

Just had a telephone consult with my GP. She mentioned that I was tested for IF in 2015 when I first came up as B12 deficient, and that it was negative. She said that I am not anaemic and my deficiency is likely down to absorption problems. I've to give more blood for another IF test and for kidney function. Next injection in 3 months.

Am I correct in thinking I may still have PA? My loading dose has been four injections over the last month. Should I be pushing for more? I don't want to jeopardise the good relationship I have with my doctor (I'm no good at anything remotely confrontational).

[Gambit62 Administrator]

pernicious anaemia is a bit of a mis-nomer. One particular form of anaemia - macrocytic anaemia in which red blood cells are larger and rounder than normal, is particularly associated with B12 and folate deficiencies. When the effects of B12 were first observed over 250 years ago - a long time before anyone knew about B12 - it was seen as a type of anaemia that resulted in madness, balance problems and death - hence the name pernicious anaemia.

We now know that what is going on is a vitamin deficiency caused by an inability to absorb B12. The mechanism for absorbing almost all of our B12 from diet is very specialised so if something goes wrong then it really goes wrong. PA is an auto-immune condition which basically attacks the process that allows B12 to be absorbed in the ileum. As such it is one specific absorption problem that will lead to a B12 deficiency.

Macrocytic anaemia is a symptom of B12 deficiency - it isn't a defining characteristic and about 25% of people don't have macrocytic anaemia when they first present. I can trace my symptoms back over 40 years and was never anaemic in that period.

Thgere are different types of anaemia - iron based anaemias tend to result in smaller red blood cells. One consequence of B12 is lowering of stomach acidity which means that you are less efficient at absorbing other minerals and vitamins which can include iron leading to both iron and B12 deficiencies at the same time which is a really difficult thing to identify - though the clue is that there will be a big variation in the size of your red blood cells - some small and some larger.

The IFA test is a specific test for PA which is the most common absorption problem leading to B12 deficiency. However, like serum B12 it-'s problematic - and gives false negatives 40-60% of the time so a negative is a long way from proving that you don't have PA - some people have the test done several times before it comes up with a negative.

loading and treatment protocols can vary a lot depending on what country you are in - the standard in the UK is 3xweekly for 2 weeks (or until symptoms stop improving if there are neurological symptoms) followed by 3 monthly maintenance shots (2 monthly if you have neurological symptoms). However, the regime in US can be very different.

It does sound as if your GP is trying to find her way through what is the best way to treat her. Relationship should be a partnership - GPs can't know everything about all conditions - it sounds like you should be able to work with her and she would be open to being guided towards the BCSH guidelines if UK based (accessible through the BNF) - just a question of doing it as suggestion and a dialogue.

[ajw1205 in reply to Gambit62]

Thanks Gambit, that helps. I'm in Scotland. I think she's the best doctor at our surgery - certainly has the most patience, but that means it can be difficult to get an appointment as she's so popular. She didn't seem offended that I'd queried things, thankfully, and did say I could go back to her with any more questions. I shall wait and see if these further bloods give up any more answers. Thanks for your help