Pernicious Anaemia Society

B12 serum and MMA

My 18 year old son had a partial cell blood test come back negative- also had endoscopy just before Xmas and diagnosed with inflammation of stomach lining . , I (mum and my father have /had PA . I'm sure the result is showing false positive for P.A, can anyone tell me what the MMA test is? I had intrinsic factor tested which showed positive result for PA. thank you . Taking son. Ack to GP in two weeks. Son has some symptoms - sighs and fatigue.

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GPC is not a very accurate test and is no longer recommended in the diagnosis of PA in the UK - usually IFA - but as that is prone to give false negatives about 50% of the time it's not a test that can be used to rule out PA.

MMA is a measure of methylmelonic acid levels - this is a by product that builds up if the body doesn't have enough B12 to change it back into a useful building block so it can be useful to clarify if a B12 deficiency exists if there is a discordance between other results and symptoms. However, it can be raised by other things so not possible to use it as a first line diagnositic tool.

Homocysteine is the same though as that can be raised by low folate levels as well and the fact that folate and B12 are used together - isn't as useful as a tool if folate levels are known to be low.

Unfortunately the symptoms of PA overlap with a lot of other things. And if there is an iron based anaemia going on at the same time - which is quite likely if an absorption problem is involved then looking just at blood work can be a problematic - iron anaemia makes blood cells small whilst B12/folate tends to make them larger - though GPs really shouldn't be using the presence of anaemia as a defining characteristic as at least 30% of patients present with other symptoms first.

However, there is always the possibility that there is something else going on.

Hope this helps a little - doesn't provide certainty but hopefully gives you some idea where you are likely to start hitting the many uncertainties around diagnosing PA and a B12 deficiency.


Is his GP aware of family history?

Family link in PA


Has he looked at lists of PA/B12 deficiency symptoms? Is GP aware of all his symptoms?

pernicious-anaemia-society.... click on Symptoms Checklist

Has he had an IFA (Intrinsic Factor Antibody)test?

This flowchart in next link gives recommendations to UK doctors on treatment and diagnosis of B12 deficiency. My understanding(I'm not a medic) is that anyone with low b12 or who has the symptoms of b12 deficiency should have an IFA test. It also says that it is possible for someone to have PA even if IFA test is negative (called Antibody Negative PA).

I'd recommend reading the whole BSH Cobalamin and Folate guidelines if you are UK based. click on box that says "Diagnosis of b12 and Folate Deficiency" should be on page 3 of listed guidelines.

I suspect some doctors may be reluctant to consider the possibility of PA in a younger person as it is sometimes I think, assumed to be a condition that affects older people. The PAS (Pernicious Anaemia Society) has members that range in age from toddlers to 80 years plus.

Have you read "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency " by Martyn Hooper, chair of PAS?

I gave a copy of this book plus PAS symptoms list with all my symptoms ticked and a copy of BSH Cobalamin guidelines to GP.

Has your son had the following tests ... serum b12, folate , ferritin and full blood count (FBC)?

If he has did he get copies of the results? I learnt from experience to always get copies after being told everything was normal and then finding abnormal results on the copies.

There can be clues on the FBC that might suggest B12 deficiency, folate deficiency or iron deficiency? Low B12 or low folate can lead to macrocytosis (enlarged red blood cells). Low iron can lead to microcytosis (small red blood cells). A person with low iron and low B12/folate can appear to have a normal MCV.

Unhappy with treatment?

HDA patient care trust

UK charity that offers free second opinions on medical treatment and diagnoses.

Your son may find it helpful to contact the PAS. They are helpful and a good source of info and can sometimes intervene on behalf of PAS members.


PAS tel no +44 (0)1656 769 717

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Hi Sleepybunny, we are in U.K (there is a strong family history of PA - the Gp tested GPC it came back negative- I've had conversation with Gp about test result and now asking for IFA test. My son looked at check list for symptoms and has at least 7/8 of them. He had a endoscopy before Xmas and they said he had inflammation of stomach lining- he suffers from very bad re current mouth ulcers as well as a few other symptoms - i (being mum) was diagnosed with PA in 2013. I have a gp appt on 13th with my son, hope Doctor will now look at the big picture and do IF test! Some of his Bloods he had done in Nov all came back at the low end of Satisfactory!


"Some of his Bloods he had done in Nov all came back at the low end of Satisfactory! "

Did you/he get copies? Sadly I lost trust in GPs i had at time after being told evrything was normal and it wasn't.....

It's possible to have severe B12 deficiency with results that are normal range. see links below. See summary point 5.

I'd suggest you consider talking to PAS before his next appt. Are you a member?


Martyn Hooper, the chair of the PAS, has said in past that it was the cases of teenagers with PA that frustrated him the most. Think he says this in his most recent book.

It's easier for the PAS to intervene by writing letters to medics on behalf of someone who has a definite diagnosis of PA which your son does not have but I think it's likely PAS could suggest useful info .

PAS tel no +44 (0)1656 769 717

Office open from 8am till 2pm every day except Sundays and some holidays.

Have you/he considered writing a letter to GP containing all your evidence eg B12 deficiency symptoms especially any neurological symptoms, blood test results eg B12, folate, ferritin, FBC, family history, quotes from UK B12 documents . My understanding is that letters to GP have to be filed with a person's medical records so are a record of issues raised. I have written polite letters in past to GPs. I also keep copies of any letters I send.

The pinned posts on this forum have useful info. I found it helpful to read fbirder 's summary of mainly UK B12 documents in third pinned post(last link in list).

As I said before my understanding(I'm not a medic) of BSH Cobalamin guidelines is that anyone with low b12 or a within range result with the symptoms of b12 deficiency should have an IFA test according to flowchart below.


Is he taking any B12 supplements? If he is these may affect his results and make it difficult to get a diagnosis of b12 deficiency.


He's not taking B12 medication, however they are treating him with buscopan and ranitidine for some of his symptoms. They also recommend omperazole, which I have been informed can I fact cause B12 def. He's not taking omperazole now.


Your son is taking a H2-receptor antagonist drug. I assume for lowering stomach acidity.

Some people with gut issues have low stomach acid not high stomach acid.

Low stomach acid and high stomach acid can cause similar symptoms but need different treatments.

Has GP considered the possibility of low stomach acid?

Low stomach acid

Found some info online that suggests H2 antagonists may be linked to B12 deficiency.

I am not a medic, just someone who has struggled to get a diagnosis.

"He's not taking B12 medication"

Has he thought about the following tests as well as MMA: Homocysteine and Active B12? All these tests are available privately if GP is unable to order them.

See links below for more info

My personal view is that none of the tests are 100% foolproof .

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