Pernicious Anaemia Society

Very confused, please help!

Hi there, I'm new here so apologies if this is in the wrong place. Basically my sister has had symptoms for years, that point to pernicious anemia. Doctors haven't taken it very seriously and pretty much none of the treatment has worked, she's miserable and desperate. She had a brief improvement from sublingual b12 dissolvable tablets, but was then put on normal b12 tablets and went straight back to being ill. Her latest blood test showed 'normal' b12 levels in her blood despite all of the symptoms returning, so Doctors are refusing to take it any further.

So my question is - can she have 'normal' b12 levels in her blood but still be deficient due to the difference between active and inactive b12? How has her blood level of b12 improved when none of her symptoms have? And if her blood levels of b12 have improved does that mean it's not pernicious anemia?

Thank you in advance for your help, you guys seem like you really know your stuff!

4 Replies

There is a significant grey range with B12 where labs say 'normal' but people have significant clinical symptoms.

Can you get hold of the actual test results - anything below 450 would be treated in some other countries, eg Japan.

The serum B12 test is not a good indicator - one reason why BSCH in UK recommends treating on basis of symptoms not test results - it looks at all B12 not the active form used at the cell - it also tells you nothing about what is going on at the cellular level.

Active B12 test looks at the active form of B12 but again doesn't tell you the whole picture and what is happening at the cellular level.

It is also possible that MTHFR might be involved - a genetic disorder which means that the body is unable to metabolise some vitamins properly - ie turning cobalamin and folate in food into the methylated forms that are used at the cellular level.

If test results are in grey area then looking at some undesirable by-products that build up if the body isn't processing B12 properly - MMA and homocysteine - may help to clarify the situation.

Is there a history of PA or other B12 absorption problems in your family?

1 like

Gambit 62's response is spot on. A B12 assay alone doesn't necessarily give the full picture.

In my case the B12 tests were on the low end of "normal," my MMA and homocysteine were perfectly normal. My symptoms continued to worsen and after four neurologists and 30 months I tested positive for Intrinsic Factor Blocking Antibodies which proved that there was a basis for my PA. The medical community has to look at the entire picture of one's health and symptoms not in isolation. Be armed with all of the test results and reference ranges from the labs.

My neurologist has a number of patients with B12 test levels above 600 who require additional B12 supplementation. It is very individualistic as to symptoms and what is needed to make one feel their best. Keep pushing to get what you need for your sister.


This happened to my own sister. Many GPs prescribe Cyanocobalamin tablets, which are inadequate to treat neurological symptoms, and, as you've realised, are not easily absorbed into the tissues but show up in the blood as so called 'normal' levels, so the patient's history and symptoms are ignored. My sister was then diagnosed with ME and dementia. After many letters, emails and phone calls, the family eventually managed to persuade the surgery to treat with monthly injections, but a lot of time was wasted and some damage may be irreversible.

This is an excellent film below and links on the same site which explain more and give advice and various templates on writing to the doctor quoting the various guidelines and BMJ research:

Hope this helps, cmbrow


Thank you so much guys, you really know your stuff and it's very helpful.


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