Pernicious Anaemia Society

Anyone able to help me with latest Haematology results ?

Latest results from Haematologist have arrived:

Homocysteine: normal 7.2 umol/L

Folate: normal 6.2 ug/L

Active B12: normal >128 pmol/L

MMA 2 days prior to monthly B12 injection: 351 nmol/L

MMA 3 days after monthly B12 injection: 393 nmol/L

The haematologist said this shows that I do not have any functional deficiency. She said that my MMA levels could be construed as 'normal' in some labs (up to 450 nmol/L ??), but could also be "influenced by other metabolic pathways independent of B12 deficiency". She has suggested Small Intestine Bacterial Overgrowth (SIBO) as a possible cause and suggested I have a breath test for this. My GP says she is not able to refer me herself as this is not available as primary care.

I don't understand exactly what is being said here.

Which of these blood tests are relevant to functional B12 deficiency at cell level ?

Is a rising MMA level something to be concerned about, or is this still considered mild (range at St Thomas' : 0- 280 nmol/L) ?

What other metabolic pathways could cause this ?

Is it normal for Folate levels to drop again after 3 months Folate treatment and retested in January (>20) ?

I'm still waiting for results from Genetics lab, one carbon metabolism and cobalamin disorders, although "unlikely the results are going to change management" and the advice remains the same: "B12 treatment at intervals of no greater frequency than that is stated in the BNF "- review in August.

Still very symptomatic, but feeling okay at the moment- had injection on Friday. Any answers to my questions would be much appreciated.

17 Replies


To my mind (I'm not a medic) if a person shows clinical improvement on B12 injections then they almost certainly had/have B12 deficiency in some form whatever the results of MMA, Homocysteine, Active B12 etc.

Flowchart below seems to support my view, look on right hand side of flowchart at bottom.

MMA article

See 5th paragraph


you are 100% right and once b12 inj.are commenced they should not be stopped there is no upper limits to b12 according W.H.O.


Thanks Sleepybunny , it's got to the point where I'm not even sure myself any more. All I do know is that I'm sick and tired of being sick and tired !


High MMA can be caused by other problems apart from low B12. Your doctor needs to check these possibilities out - especially kidney function.

I don't think the genetics tests will provide any useful information as, unlike the process where methylcobalamin is involved the MMA process isn't a one-carbon process.


Thanks fbirder , been off sick for a year in September and don't feel like anything's been resolved at all yet. My GP has already checked for any alternative reasons for raised MMA and have had liver and kidney tests etc. so happy about that.

Genetics test results seem likely to show nothing and MRI brain scan results seem to have gone missing. Trying to sort out the breath test for SIBO as soon as possible. That's it then, I think.

Yes, no, high, low.....still feel like cr*p.


This article gives some explanation of the other factors that can cause raised MMA

it gives the normal range as <.4nmol/mL = 400nmol/L, which would mean that your levels are normal.

Not sure about the SIBO - that actually sounds like something that would be an alternative to PA as an absorption problem leading to low B12 (though it is mentioned as a cause of mildly high levels in the article above). per sleepybunny I'm not a medic.

Folate is very responsive to dietary intake and isn't stored in the body. If your original deficiency was due to an absorption problem rather than lack in your diet then quite likely it could recur - however you are unlikely to need the huge doses that you were given or the previous deficiency and should be able to get buy on supplements from the supermarket.


Hi Gambit62 , looks like my MMA levels (393nmol/L) are heading towards 400nmol/L, so I'll just wait for that to happen. Getting good at waiting.

As for dietary intake, I'm a vegetarian and have been for a (previously) healthy 35 years- my diet is largely made up of eggs, cheese, leafy greens and all other vegetables (except celery !) and fruit, so cannot explain B12 deficiency or low folate levels. Can't be dietary. Could be SIBO - bacteria are greedy vitamin-grabbers apparently - so would quite like the breath test to be done soon as possible. Maybe the answer is to eat NONE of the above and starve them !


SIBO can increase folate levels as the bugs themselves make it.


Well I never, fbirder . In blood tests ? More complexity. Could it explain original low B12 level though?

Sooner the better with the breath test then.


I have read one paper that looked at folate levels in people with achlorhydria (lack of stomach acid). They said that the lack of acid decreased folate absorption, but that blood levels were normal because of achlorhydria-induced SIBO.

This paper showed that bacteria in the small intestine can produce folate and that said folate is absorbed.

So SIBO should be able to result in raised folate levels in the blood.


Any easy way to measure stomach acid, fbirder ?

Having problems getting return call from haematology, so trying to find out what to ask for next / what is a reasonable assumption, and brain has ground to a halt today, not even a week after injection. Don't you hate it when that happens? Way too soon.

Thanks very much for your help and will print off information in the hope that I will be able to absorb at least this.


I asked my gastroenterologist about measuring stomach pH and he said it's not possible. What he meant was it's not easy.

There is a method where you dissolve a teaspoon of baking soda (sodium carbonate) in water and drink it on an empty stomach.

It will react with any acid present to produce carbon dioxide - which will try to escape as a lot of burps.

When I try that I get a couple of little ones (probably from swallowed air).

The gastroenterologist said it sounded silly.


....sillier than "B12 is highly addictive" (haematologist) ?

"Well this sounds cheap and harmless, so why not ?" (me)

Thanks, fbirder, will let you know.


B12 is addictive. Just like dihydrogen monoxide.


True. So why so afraid? Feel like they are trying now to find any answer that does not include either B or 12 in it!

Anyway, back to our own research:

About ten minutes later, I managed to produce one solitary sorry excuse for a burp, so apologetic it was almost begging it's own pardon on the way out. My partner then volunteered, and is probably still burping loudly (and rather smugly, I have to say) now. Just to check what "within normal range" is like !


what is normal?? what the doctor says???


Funnily enough, my doctor checked my MMA levels as she suspected Functional B12 deficiency, found they were raised - 351nmol/L at that time (range 0-280nmol/L) - and checked all other likely reasons at the same time. Functional B12 deficiency was confirmed by the lab.

Now it seems that Haematologists don't think so - and MMA not high enough at current level of 393nmol/L, and are waiting for it to be 450nmol/L, I think, before it is considered to be above normal levels.



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