I have Pernicious Anaemia and have been struggling with symptoms returning earlier and earlier. I am now at 8 week intervals. I asked to see a haematologist. She was singularly unpleasant, and had a real problem with myself and my wife having obviously done some research and that as a result we were well informed. She grudgingly agreed that the blood tests are rubbish and not to be trusted and then in the same breath declared the reading to show me 'swamped with enough B12 to last 3 or 4 years'. My reading was in the 800's. She also said that even though I have enough to last 3 or 4 years, I should continue to have a jag every 8 weeks, so she seemed to be at odds with herself! She told me bluntly my returning symptoms were NOT due to B12 deficiency but were more likely to be low blood sugar. We decided we would be prudent and follow her advice to add, and spread, a few more calories into my diet, rather than dismiss what she was saying simply because she was so unpleasant. So, for the past 2 weeks I have done what she advised, and added a few more calories (about 300 a day) via nuts, lucazade and the odd biscuit. It certainly seemed to help but now I see that I have put 4 lbs on in weight and my 'fluttery' tummy is just beginning to come back again. My next jag is due in 1 week. Can anyone tell me if a lack of B12 is also capable of causing a drop in blood sugar?