I have been around a long time and read every day. I have a hard time understanding what a functional deficiency mean. In my case just a few injections brought my MMA and homocysteine down very quickly. Is that a functional deficiency? Seems like I would understand this by now. I have never seen a B12-literate doctor so I have always been on my own...from diagnosis to treatment. I now have a doctor who is checking my MMA and homocysteine yearly but that's all. I buy all my B12 from Germany and don't even talk about it with the docs although my doc insists that i should be injecting IM (i find SC easier and less scary than IM...my only reason.)
Thanks for your help.
Eileen
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What is MMA please? I too am new here and lurking hoping to understand what it is I’m doing. SI IM is working for me, following guidelines but feel a little like I’m experimenting without expert oversight 🤣
Sorry I don’t wa t to hijack the OP question. But I think my query is similar.
If I’ve already started SI IM following advice and supplement B Complex too, how would I test MMA meaningfully?
Would I need to become deficient and be symptomatic again? The tingles return within a few days of stopping the B Complex. Can’t figure out what the SI is doing for me, I’m guessing the ’improvement over longer time’ is what I am still working towards there. GP hasn’t a scooby, neurologist didn’t pick it up, MSk specialist didn’t pick it up. Is there a benefit to me testing my own MMA should I ask GP?
For me it showed me that the B12 was getting into my cells and not roaming around in my blood. Before injections my MMA was over 1.04 (high end .25) I didn't test again until after treatment. It dropped about 50% after two injections. My doctor ordered a serum B12 (I told her not to and my B12 was up, within a year to 962) I no longer test serum B12. I test homocysteine too. Sadly mine has gone up slightly, but it went from 25 to 13 (high end was 12, I think) It took longer for the homocysteine to come down.
Functional deficiency occurs when the body seems to have sufficient B12 by serum B12 and/or active B12 testing but deficiency symptoms exist because for whatever reason, the B12 is not reaching the cells where it is needed. This is usually indicated by a persistently raised MMA. Problems with transcobalamin II (the active transport protein for B12) are probably implicated in many functional deficiencies.
But MMA (and Homocysteine) are often raised in common or garden B12 deficiency and are not specific to a functional deficiency. When B12 is repleted, MMA and Homocysteine normally correct very quickly as normal metabolism resumes. I know of a case where this did not happen quickly (with MMA), in a functional deficiency. I don't know the biochemical reason for this, although clearly there must be one.
Here is a reported case of functional B12 deficiency:
Hi Technoid, I responded yesterday but do not see my response here. Mostly I just wanted to thank you for your patience and succinct explanation to my question. I guess I did not have a functional deficiency. I feel lucky about that.
Functional B12 deficiency ; if there is something wrong with the process of getting B12 to cell/tissue level where it is needed, then MMA can build up within bloodstream even when B12 is introduced. This is because the link between the B12 and the MMA is not happening well enough or often enough to reach cell/tissue level in sufficient quantity.
I started with slightly low B12 - just low enough to be out of range - so was given B12 injections. Because I continued to deteriorate, my GP wanted to check that the process was working. She tested my serum B12, my serum MMA and my renal function among other things. My B12 was very high, due to the injections, my MMA was raised. Because she had eliminated renal problems as the cause, she was able to diagnose functional B12 deficiency which was confirmed by the testing laboratory. Later on, SIBO was ruled out as a possible cause.
From that point on, I was given 2 B12 injections a week for 6 months. Then a maintenance dose : one injection a month - which failed to maintain improvements. I started self injecting B12 -firstly EOD, then after a couple of years every third day.
Despite the frequency of injections, I still had raised MMA for three years. On the sixth test, it had finally dropped into range. It has not been tested since.
Over the past six years, all else has been ruled out. I continue to self inject and can, by and large, control most of my symptoms most of the time. Folate, ferritin and vitamin D need monitoring - as the first two can be erratic, and the last is on prescription as I have osteopenia of the spine - thankfully now reduced from osteoporosis.
If you are deficient in B12, your MMA can build up in your bloodstream (sometimes to very high levels if it goes undiscovered or untreated for a while). This should reduce quickly once B12 is introduced - so by the time that the loading injections are completed, MMA should have returned to a normal level.
If not, and if despite the B12, symptoms are worsening, there is likely to be a malfunction in linking/transporting to where it is needed. Two alternative possibilities for raised MMA and B12 deficiency: renal problems and small intestine bacterial overgrowth (SIBO). These can be ruled out as causes by a blood test (renal problems) and a fasting breath test (SIBO).
If a genetic cause can be found for this in DNA studies, the consultants will advise GPs to give two B12 injections per week for life. Luckily, this condition is rare.
I am so glad that your MMA did respond so rapidly.
Most people have no idea what their MMA is doing prior to B12 injections - as the MMA test is not widely available here in the UK (and is probably expensive). If your need for B12 injections is not in dispute, then there is no need for a secondary test that costs a lot. A low serum B12 result plus indicative symptoms should suffice. But this of course is entirely dependant on what an individual GP (or practice even) would consider "low" and what symptoms they understand as attributable to B12 deficiency. Since many can be as easily interpreted as indicating other conditions, or else signalling generic vitamin deficiency/ malnutrition, you can already see how difficult this might prove for some.
Add into the mix the need for an early Pernicious Anaemia diagnosis - (to ringfence future treatment) - without patient/GP awareness that the IFab test even exists or that it will only give a positive result in 40-60% of PA patients, OR that a specific cause for the B12 deficiency may become important later on .... well, it becomes a bit of a minefield, doesn't it ? For all of us.
When I was first told that I was B12 deficient, I didn't even know there was a B12 to be short of ! I didn't know either that there would be further treatment after the six loading injections. So I certainly wouldn't have known what to ask for.
UK GPs will need to be able to access the MMA test quickly and easily locally if the new NICE guidelines due out early next year are to be followed, since it is advised that, for those with borderline serum B12 results but symptoms that would suggest B12 deficiency, this should be the secondary test used. For this to be at all useful, it will need to be done prior to administration of B12 injections - and I am concerned that this will either mean a logjam of requests causing delays in treatment, or that this advice will be ignored as expensive and unworkable as so few local hospital laboratories are able to provide this service.
Let's hope that, instead, GPs just get better at recognising early B12 def symptoms, making the MMA test's use as secondary confirmation redundant !
I went to see a new GP today - since they called me to make an appointment -and I now have some blood test requests. I phoned up to book the test on the number given as soon as I got back home. The soonest available is a week away. The GP said allow another week for the results to come back and be checked, then book an appointment to discuss the results .... I can already guess that the main focus will have altered from the benefits of statins to explaining why my B12 is off the charts !
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PLEASE HELP WITH SUSPECTED B12 FUNCTIONAL DEFICIENCY
Functional b12 deficiency 
Functional B12 deficiency?
Apologies, still not clear. Not PA but referring to 'functional B12 deficiency' only.
