'normal' range is set assuming people haven't had and are not on B12 shots - it doesn't really mean a lot if you have had B12 shots as these introduce new factors into the equation - one of which is the possibility that you react to the high levels of B12 in your serum by producing antibodies that stop the B12 getting from your blood to your cells where it is needed. This isn't a problem if you have an injection until your serum levels fall below the point where there is enough in your blood to beat the reaction. It is a bit like having built a dam but still needing water down stream - as long as the water levels behind the dam are high enough for water to trickle over the top things are okay but once they fall below that level no water gets trhough.
so, 400 (pmol/L or ng/L) may well be in normal range but it may no longer be in the range that is okay for you.
Try talking to your GP about moving from 12 weeks to 8 weeks - particularly if you have any neurological symptoms - tingling in hands and feet - though even that may not be frequent enough.
You could also suggest to your GP that they take a look at this part of the PAS website particularly geared towards medical professionals and helping them to understand how patients really respond to B12
test results are about averages in particular circumstances but people aren't averages and if the circumstances are different then they are even more likely not to correspond with averages.
You mentioned on another thread that you've been having B12 injections for 7 years. I don't think a level of 400 is very high for someone who has had injections for years.
Have you been diagnosed with PA (Pernicious Anaemia)?
PAS (Pernicious Anaemia Society) can offer support and information to its members.
In UK, people with B12 deficiency with neuro symptoms should have a loading jab every other day for as long as symptoms continue to get better then a jab every 2months.
Undertreated B12 deficiency can lead to permanent neurological damage including problems with spinal cord.
PAS news item about neurological consequences of PA
In my opinion, it's easier to argue for increased B12 injections with proof of PA diagnosis.
"...lot of neurological problems my forehead is numb also the sides of my face and shoulders.....electric shocks up my spine .... constantly got back ache "
I'd urge you to contact PAS and ask for advice.
People who are symptomatic for B12 deficiency are at risk of developing spinal problems if their B12 deficiency is not treated correctly.
There is a PAS article about SACD, sub acute combined degeneration of the spinal cord, available to PAS members.Some people on forum have shown this to their GPs as an example of the consequences of being undertreated.
Person who runs this website is supportive and sympathetic and can be contacted by e-mail. Details on website.
"I will look up all the sites and have a talk to my GP"
Some people find it helpful to write a letter expressing concerns about B12 treatment. See link about writing letters in post above.
My understanding is that letters to GPs are filed with medical records so are a more permanent record of issues raised. Things said during a consultation may get forgotten.
B12 books
These are books about B12 I found useful.
"What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper
Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book is up to date with UK B12 guidelines. I gave a copy of this book to my GPs.
"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper
Has several case studies.
"Could it Be B12; An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)
Very comprehensive book about B12 deficiency with lots of case studies.
B12 deficiency is not as well-understood among doctors as it could be, in my opinion, so I'd suggest doing your homework on B12 in case GP has not done theirs....
Lots more B12 info in pinned posts on this forum. I found it helpful to read fbirder 's summary of B12 documents. Link to summary in third pinned post.
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