I'm still trying to get to grips with the details of my issues, having finally see some possible light at the end of a long tunnel. I did search for a similar post, so apologies if I've missed one.
As I understand what I'm reading, PA is a macrocytic anemia, so would normally result in a high MCV on the blood count.
My neurologist requested a Full Blood Count along with other things, which is what showed up my low B12 (118 ng/L). However, the blood counts don't seem to match up with a 'usual' PA case?
The ones I think are relevant are:
MCV 85.1 fL (Range 80-100)
MCH 28.5 pg (Range 27-34)
MCHC 334.0 g/L (Range 315-345)
(Others available but I won't make the post too long by putting them all)
I am due to have the IF test on Monday, so hopefully that may clarify things (I'm aware of the low sensitivity of this test).
I think have read somewhere (can't find where and I've read so much in the last week my brain is muddled) that PA can occur in a small percentage of people without the usual raised MCV.
(EDIT - i think I found the reference - the British Journal of Haematology guideline
"The absence of a raised MCV cannot be used to exclude the need for cobalamin testing because neurological impairement occurs with a normal MCV in 25% of cases (Lindenbaum et al, 1988; Healton et al, 1991).
That doesn't seem to necessarily relate directly to PA though, just B12 deficiency..).
I've also read that an Iron deficiency can lower MCV, and thus iron deficiency and PA together can cancel each other out with regards to this result.
Unfortunately, the blood test doesn't seem to have tested iron (would show as ferrite on the test I believe?) - and I'm not clear if any other markers would suggest that?
I'm guessing that it will be worth getting my iron checked to rule that issue in/out (If it hasn't been tested in previous blood tests over the last couple of years)
Failing that, I guess my rather meandering question is whether a low B12 with a 'normal' MCV is more likely to mean iron deficiency + PA, or PA without classic large cells - or possibly an alternative non-PA cause for the B12 deficiency?
It's fairly clear that I may have do to much of the investigative work if I want to get to a final resolution, so any ideas on what I should be reading up on/investigating would be appreciated.