pernicious anemia and peripheral neuropathy

please would you be kind enough to tell me why my gp decides to take a blood test to check B12 one week after my injection of b12.  I do not see the point.  Should the blood test bbe done before the B12 injection?  Also I have been feeling dizzy, headaches, and even nauseous.  I also have pins and needles in my hands, legs and feet on fire.  THE GP took blood pressure which is low when I stand up or sit down but high when I lie down. I know that deficiency of B12 is the cause of the peripheral neuropathy and am having test done nxt month. Please help me because I am so tired and being a carer when I feel so dizzy and sick, is not joke.  I am 64 years old and use to be on B12 tablet and folic acid previous to my injection.  In my opinion it does not make sense to take blood test after the injection. Thank you

Hi Catherine,

i agree it makes no sense to test after the injection, you want to know how low the levels are before the injection. The pins and needles are a symptom of low B12. I wonder if your Dr might be checking to see if you are producing antibodies or intrinsic factor? If you'd previously been OK on tablets, it may be that you are not producing what you need to use the B12 in your digestive system anymore. Possibly worth asking your Dr when you next see them, or ask the nurse/phlebotomist when they take the blood sample, what are they testing for? Do hope things improve for you soon, with best wishes Marion

Hi Catherine Marion raises a salient point, and that is to determine why you are B12 deficient. Often women get hypothyroidic later in life (they don't know why), and this eventually causes you to become B12 deficient. It doesn't really make much difference, however, if you are hypothyroidic you will be low on FAD (this comes from riboflavin metabolism) and you won't be able to respond well to cyanocobalamin and you will need combination methyl and adenosyl cobalamin (Cobalamin is another name for vitamin B12). Cyanocobalamin is a provitamin form of vitamin B12 and many people can't modify it to form the two active forms, methyl and adenosyl cobalamin. Have you responded to the injection yet?

Makes no sense to me either.  A test immediately before a jab (to show your prevailing level), and another some time after (to show what you are able to retain from the jab) would seem more logical.  You sound pretty poorly.  I suggest you speak to your doctor and ask them to explan.