Methylmalonic acid

Methylmalonic acid is another important component in diagnosing vitamin B12 deficiency anemia.   Just because you have a blood test where your vitamin B12 levels are low, doesn’t necessarily mean that you have B12 anemia.  Your doctor will determine the amount of methylmalonic acid in your blood by ordering (yet another – get used to it) a blood test.  This blood test will help determine whether or not a vitamin B12 deficiency exists.

According to, the definition of methylmalonic acid is a dicarboxylic acid that is a C-methylated derivative of malonate.  In easier terms, the methylmalonic acid in your body is a substance that is produced when the amino acids in your body break down.

The methylmalonic acid test is primarily ordered by doctors for help with diagnosing B12 deficiency.  It may also be ordered to check for certain genetic disorders such as methylmalonic acidemia.  Testing for methylmalonic acidemia is usually done as part of the many blood tests performed on newborns.

While range values can differ depending on the laboratory that performs the test, normal methylmalonic acid levels are usually considered to be from 0.08 to 0.56 micromoles per liter.  If your values are greater then what the normal range indicates it might be due to vitamin B12 deficiency.  It can also indicate a genetic disease (methylmalonic acidemia).

Once you have been found to have low levels of vitamin B12, the methylmalonic acid test will be ordered along with the test for homocysteine levels.  It has been suggested that using the methylmalonic acid test as a screening tool to discover B12 deficiency would be beneficial, especially with the elderly.  However this is very controversial and only a handful of doctors use the methylmalonic acid test for this purpose.  If your methylmalonic acid and homocysteine levels are normal it is unlikely that a B12 deficiency exists.  Even if vitamin B12 levels appeared low in previous tests.

Methylmalonic acid levels may also be increased with kidney disease.  The methylmalonic acid accumulates in the blood and is not excreted in the urine.  While an elevated methylmalonic acid test may indicate a B12 deficiency, the levels of methylmalonic acid does not mean anything specific when it comes to the B12 deficiency.  The symptoms you feel, the severity of your deficiency or the likely hood of any progression are not based on the number that results from your test.  It has been found that there is a high variation rate in methylmalonic acid tests when they are continually measured over time.

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19 Responses to “Methylmalonic acid”

  1. Lynn

    Just curious, my daughter’s serum B12 came in at 223. The doctor immediately started injections and said that she lacked intrinsic factor. He didn’t do any further tests. She does have other autoimmune conditions. Is it okay to assume she lacks the intrinsic factor without confirming it. He did not check her MMA or homocysteine levels after the low serum B12 came back.

  2. B12 Anemia

    While I am glad that your doctor started injections quickly, I am surprised that he did not check her MMA or homocystine levels. It would have been good to know the results. It wouldn’t worry me too much though. It may just be that he felt confident enough to rule out other factors if she didn’t fit any other criteria or from what he already knows about her other autoimmune conditions. Many times they never find the cause of the deficiency anyway. The most important thing is that she is getting the B12 shots and can start to heal.
    Good luck with your daughters recovery.



  4. Hazel

    Sorry just needed to rant, im so frustrated that my results came back at 118 (B12) and my doctor hardly blinked, he just said we’ll start you on injections, ive been progressivly getting sicker for a year and a half, i had to stop working, i cant really drive because of my light headedness and visual problems are so bad! I really dont think he understands b12, he didn’t suggest we find the root of the problem (MMA) or anything and does not belive my symptoms over the last year and a half are connected to B12 which include; exhaustion, light headedness, loss of balance, very bad muscle pain in my legs and feet followed by a burning sensation, stomach problems, forgetfullness, confusion, anxiety due to continued symptoms and probably more im forgetting. I was the one who insisted he check my levels twice, the first time he tested them they were 210 five months later they were 118
    Perhaps its not the same as B12 symptoms i just wish my doctors could figure it out
    Thanks for letting me rant!

  5. B12 Anemia

    Rant all you want, that’s one of the reasons I created this site. I can tell you that I had almost all of your symptoms and believe me they are caused by B12 deficiency. My doctor even showed me a whole medical printout with the symptoms of B12 deficiency and I saw with my own eyes that exhaustion, light headedness, loss of balance, forgetfulness, anxiety and neuropathy (muscle tingling/pain) were among the symptoms listed. Your doctor definitely should have checked your MMA levels, that is the way most doctors can gage what type of B12 deficiency you have. How often has your doctor started you on shots? With a level of 118 I would be demanding at least one shot a week for the first 8 weeks. Some doctors are even more aggressive with treatment and start you with a few shots a week, than taper them off. Your doctor doesn’t seem to have much knowledge about how serious this condition is, so I would definitely suggest finding a doctor who does. I went to many doctors before I found one that took B12 deficiency seriously.
    Good luck!

  6. Hazel

    Thanks for that, its so nice to hear others have experienced the same, his put me on fortnightly injections over three months, i had the first injection on Tuesday last week, i felt a clarity i hadn’t felt in what feels like years but by Sunday all my symptoms came back ten fold i have another week to wait for the second injection.
    I’ve seen so many doctors, had so many tests, since this started, my Neurologist told me about three months ago there was nothing else he could do for me and asked if it could be psychological at which point i kind of gave up seeing doctors, if i change doctors again im just afraid they’ll label me a hypochondriac. Any chance you know any b12 friendly doctors in melbourne australia? lol thought it was worth asking

  7. Kerrie

    After discovering most of my maternal side of the family had B12 deficiency, and I started suffering from extreme exhaustion, light headedness, forgetfulness, sore tongue, etc I decided to badger my GP for a test. I was told repetitively there was no ways could be B12 deficient, and that’s how I should feel after having a child. My child at that point was 9 months old and had been sleeping through since 8 weeks, allowing me around 9-10 hrs sleep a night! I badgered enough to get a blood test that showed I was deficient in both B12 and iron. They queried dietary issues with me but then, like Lynn (above) daughter they decided I must lack intrinsic factor as 3 years of supplements as well as a decent dirt had still left me with a quite low level. No other tests were performed and I was told I also not technically anaemic as the two deficiencies were leading me to have normal sized blood cells. I was put on a jab a day for 2 weeks then further jabs every 12 weeks. I can often feel my symptoms returning around 8 weeks. As I’m pregnant again now, two GPs have upped my jab regime to 8 weeks. Being due another 8 week jab this week, I called into my surgery and got the original GP who tried to refuse my test before. This GP again told me I wasn’t deficient, blood tests had proved it to be dietary, and I was obviously too lazy to eat well or take the tablets. I argued until I was given another blood test, and this time my serum b12 is low normal. I’ve been trying desperately to find out what tests I can get done so I can actually find out what is wrong with me. Am hoping I can badger them into an MMA test too. As a side issue, I’ve also discovered I’ve lost immunity to rubella, so I have an antenatal consultant concerned I have the auto-immune deficiency side, but I’m stuck as no one will take ownership of this. Rant over here too!

  8. Hazel

    Hi Kerrie
    Im having as much trouble as you! Its very frustrating
    I currently feel completly defeated, after waiting two weeks to see my doctor i told him i wanted to find the cause of my defiency, he responded ‘there are no tests, your deficent, take the injections and dont think about it’ , i was lost for words, i’ve been ill really ill for a year and a half and he still links no connection from my symptoms for the past year to the discovered B12 Difiency, im really upset, i want a doctor that helps not one that doesn’t seem to have a clue :(

  9. Kerrie

    Hi Hazel,
    Its so frustrating isn’t it? I’ve had so much of this particular GP that I’ve now moved surgeries. If someone would just write on my notes that I’m to be treated as if I have malabsorbtion issues, I’d hopefully get far more consistent treatment. I know there’s an antibodies test that can show if its a certain type of deficiency, and I’ll be demanding that after baby is born. Very glad I can normally just about cope with the 12 week routine at a push normally. These GPs that don’t seem to care can’t make life good for those of you that need B12 more regularly.

  10. Minnie

    Ok…. After reading these comments and experiences, I have decided that I was apparently correct when I finally decided that doctors just are not very good at what they do anymore. Not do the care. I have experienced all of the symptoms described by many here…. My doctor offered antidepressants until I finally got angry and told him to keep his antidepressants and get his kick-backs via another patient. My symptoms persist. My allergy specialist did his own blood work and said that my B12 was low…the regular doctor says it is fine. When I asked him to explain the descrpency, he just blew it off and said that taking shots wouldn’t hurt anything! I don’t know what to do!!!!! I feel terrible most of the time. A shot helps for a few days but then I’m back to exhaustion. I truly don’t know where to turn….. I am certainly open to suggestions!

  11. Judy

    I guess I am one of the lucky ones. After asking my doctor to test my B-12 she was happy to do it. Also tested my Methylmaonic Acid – wow my value was 1731. She said I do have a problem absorbing the B-12 and definately needed shots. Took 1 a day for a week, then 1 per week for a month and now take shot once a month. By B-12 levels are coming up from 156 to 548. If at the end of the month I start feeling symptoms I pop a B-12 (sublingual) under my tongue for a few days and feel better. You can buy the B-12 sublinqual at any pharmacy. I also found out that I have a Vitamin D deficiency that could go along with the B-12 deficiency and I am taking high dose of Vitamin D to help get it up.

  12. Kerrie

    Had a rather interesting chat with my new GP today. Seems I got lucky and he knows quite a lot about B12 deficiencies. Turns out the doctors are being hampered by the latest NHS directives, so if you have a proven malabsorption or immuno deficiency doctors can work with you and give jabs at frequencies that help. Anything else is considered dietary and tough, you have to wait 12 weeks. Even he knew the issue is that most people aren’t being given the proper tests before jabs are given, so therefore are being viewed as “it’s all your own fault” and also that you can have a malabsorption issue other than lack of intrinsic factor, but it’s hard to get these tested for under NHS. I’m now being given test for lack of intrinsic factor and/or presence of antibodies but even he’s not sure how the jabs are going to affect these tests, and has said they may need to starve me of B12 and rerun (at some point after baby arrives and I’m settled at least). It’s so stupid how trapped you can be by being unlucky enough to have a GP that doesn’t understand certain conditions,

  13. Hazel

    i just wanted to let you know that it does get better, my levels came back at around 118, i had been sick for a year and a half, i had to stop working, my symptoms were dizziness, off balance, light sensitivity and visual disturbances, sever leg cramping and many more, i started on shots and after the first shot i felt great only for two days then i seemed to crash and all my symptoms came back worse than before, after my second shot i felt good for about four days, after my third i felt good for two weeks i coudln’t believe it, i’ve now had my forth shot and feeling ok, my symptoms are still there but managable, there not sever anymore. I’ve been having shots on fortnightly interviews. It is so disappointing that my doctor refused to check my syrum levels or test why i was deficient, or link my symptoms to the deficieny hoewver i can tell you after trialing medication for all sorts of things they diagnoised me previously such as epilepsy, migraines, ear infections etc nothing has helped but these shots, keep getting them they take time but do work, My doctor told me on monday i would need to continue taking shots at three monthly interviews once i initally had six shots at fornightly intervals
    hope that helps

  14. Hazel

    Can i ask if anybody is from Melbourne Australia and if they have a good GP that understands b12 Deficiency ?

  15. Bill

    I came along your website after searching for answers for so long, My daughter is going thru a lot of conditions that being B 12 deficient show, Light headed, numb hands and feet, burning, anxiety, spacey feeling, exhausted, sometimes she just is so exhausted from talking she seems short of breath, I took her to the doctor and demanded a CBC test which they said everything was normal, I told them to do a MMA and 25 Hydroxy test for Vit D, they keep pushing off she has any type of B 12 Problem however I told them she is a Vegetarian and has been for years, she also has just given birth to her 2nd child 6 months ago and did not take any type of supplements while she was pregnant!! My mother took b 12 shots for years and years, The MMA tests came back today and the doctor had just called her and told her they were normal, her MMA test results came back at #102 is this normal,?? what else can I do or ask to be done to find out if this is really a B 12 Problem ? I also have to note I had given her a Spray B 12 methyl and told her to use it twice daily and a sublingual b 12 and told her to take ONE a day and honestly I see a difference in her after 4x 5 days however she doesn’t think Im on the right track and wants to listen to her doctor which has her on adavan and wants NOW to start her on something different and shove her off to a Psychiatrist, should I demand further testing and what could be used, I heard about a UMMA, still waiting for the Vit D test to come back, Any help will be greatly appreciated!!

    Thanks so much,
    Anyone with any help at all can email me @

    I just dont know where to turn or what to do next,

  16. Carl


    Before Christmas I had two B12 tests – one was just below normal the other just above normal. I requested an MMA test – but was told that they do not do them!!!! I was told to have another test in about six weeks – hoping to have it today. I have had abdominal pain for a few years – have had all kinds of tests – all have proved negative. I have also noted that a lot of my endocrine test results are just within the normal range. I may have to pay for the MMA test myself!!! B12 deficiency could account for the above. Have been eating Marmite to see if it will increase B12 levels. But I really think they should give me an MMA test. Problem is I was diagnosed with ME – so I think all my syptoms will be attributed to that.

  17. mimm

    I was diagnosed with chronic autoimmune gastritis -so b12 not absorbed. i’ve had anemia for yeras without a cause-dr said do b12 injections. I do anemaia infusions too.
    after did b12 shot did bloodwork this inclluded the mma and b12 bloodwork– but after b12 showed normal at 20mma
    and 2000 b12–shot was 1000 b12- so now these values are off rihgt?? any idea how much an mma is scewed after 1000 b12 ahot??

  18. Kim

    Question….I have been diagnosed with hypothyroidism, however my labs were all within the normal ranges. I have had tons of tests and labs done and I am feeling so much better. In September I had facial numbness and tingling, along with extreme fatigue, confusion, forgetfulness, night sweats, insomnia (at times), etc. since starting Naturethroid I feel much better, I am also taking multiple supplements and vitamins. I was just looking over labs I had in November and saw the following:
    METHYLMALONIC ACID 57 (87-318) LOW!?!?
    FOLIC ACID >20 which is normal
    VITAMIN B12 675 (200-1100)

    I have been taking a vitamin b12 sublingually since Jan 31st. A new doc wants to check vitamin b12 and vitamin b6. What does the low Methylmalonic acid result mean and since I have been supplementing since Jan 31st should I see results with the new lab that has been ordered? Thanks for any help!

  19. Susan

    I just received the results of my last monthly blood test. I have an IGG & IGA deficiency so I get IV’s usually every 2 months. On my last blood test my hematologist also checked my MMA. It was higher than the highest range listed (what is considered to be in the normal range). I have many of the symptoms above and for the past 3 years I have been treated for a neurological disorder as well. They have called it essential tremors because they have no other diagnosis. I am wondering now if I have a B12 anemia?