Methylmalonic acid test preparation

[Nicksi]

Wondering what people's experience is with MMA test, and any suggestions about length of time between last injection and blood sample taken to get the most accurate reading.

many thanks !

[fbirder]

The reading you get will be accurate, no matter when you take B12.

Whether or not you stop injections depends on what you're trying to find out from the test.

If you want to see if you have a functional deficiency, where you have plenty of B12 in the blood, but it's not getting into the cells, then it makes no difference when you have an injection before a test.

If you want to see if you would be deficient in B12 if you stop your injections then you'll need to wait at least three months, preferably six.

[Nicksi in reply to fbirder]

Ah ok, thank you for explaining that!

[Cherylclaire Forum Support]

I had serum MMA tests done 5 times. The first time because my GP suspected functional B12 deficiency - this diagnosis was confirmed by the lab because my MMA was raised, 8 months after my first loading injection. Although my B12 was by then over 2000 ng/L (measurable limit) I was still symptomatic - and worsening on a 3 monthly injection regime.

Later Haematologists tested it 4 times in total. Once was just prior to my B12 injection and then again a couple of days after it just to see what was happening: it actually went up from 351 nmol/L to 393 nmol/L.

My MMA, considered "raised" rather than "high", at a fairly constant 350-400 nmol/L

(with a range of 0-280 nmol/L), was eventually dismissed as being my "normal".

When I have seen consultants, they say that with functional B12 deficiency, they would expect very much higher MMA results. My GP however believes raised MMA to be rare and has seen it only twice in 20 years of medical practice - the other patient had a functional B12 deficiency diagnosis 10 years previously, which is how she remembered about MMA testing.

My DNA was tested and nothing was found to suggest an inherited functional problem.

Still, in the absence of any other diagnosis, I treat myself as if I do have a functional problem :

I find I am generally able to control my symptoms by frequent injections, but not eliminate them completely. Some are still daily and I still get consequences if I do too much physically. When I try to reduce injections from 1 injection every 3 days, other symptoms return and remaining ones become more severe. I personally find cognitive problems the most difficult to live with.

Renal problems were ruled out by a blood test by GP initially as this can raise MMA.

Small intestine bacterial overgrowth (SIBO) can also be a cause both of raised MMA and B12 deficiency. A fasting hydrogen breath test can rule this in/out. This can be difficult to eradicate - antibiotics are used in treatment.

fbirder is quite right in saying that it makes no real difference when you have your injection prior to testing, for functional B12 deficiency. I would just add that it is possible to get an inconclusive result from this, in case you are pinning your hopes on one test giving you your Answer. I know how frustrating and disheartening this whole process can be.

Hope you get answers soon.

I am not medicallly trained. This is just my own experience.

[Nicksi in reply to Cherylclaire]

Thanks so much for sharing your story, It definitely is frustrating, especially my new GP who keeps repeating that my B12 is normal at 300 and doesn't know why I have all these symptoms (the neuropathy being the worst of them). Like you I've been self managing with injections, and lately being a first time mom who is breastfeeding, I've need more injections almost dailyjust to abate the symptoms. This GP has sent me to a hematologist and that's the test hes ordered.

I wish I got a doc that would order the tests like you described just to get a better picture. Instead I keep getting my serum result thrown in my face by this doc. Even though I was originally diagnosed because I had undetectable levels and peripheral neuropathy.

I'm only getting this one MMA test done,they aren't even checking anything else

So fingers crossed!!

[Cherylclaire Forum Support in reply to Nicksi]

I'm lucky that I have a supportive GP, who has noticed for herself what works and what doesn't when treating me.

After she got the diagnosis confirmed, and after starting me on injections at 2 a week, she told me she wouldn't need to test my B12 again because she knew it would be above the measurable range, so there would be no point- but would continue to monitor folate, ferritin, vitamin D and thyroid.

As you can see, there wasn't much difference in any of the MMA test results that I had- all 5 were above range. Who knows now how high they were before I had B12 injections or where within range my normal lay prior to that ?

One test will do it, I would think.

The haematologists that I saw warned me that B12 was "toxic/carcinogenic/highly addictive", depending on who I was talking to: all very alarmist and anti-B12. No proof obviously, although I asked for evidence three times. One of them decided my cognitive problems, dizziness and air-hunger were because I used to smoke- and so my brain was starved of oxygen !

All this led me to believe that they were only testing me so often to rule out functional B12 deficiency by finding a "normal" reading for MMA- or else an alternative reason for it being raised.

SIBO for example.

[Nicksi in reply to Cherylclaire]

That great you have a supportive GP! I'm hoping the hematologist I'm about to see will be knowledgeable

[Cherylclaire Forum Support in reply to Nicksi]

Me too. Crossing my fingers.

[Cherylclaire Forum Support in reply to Cherylclaire]

Heard anything yet, Nicksi ? Hoping for good news.

Here's a strange thing:

I was rereading my final DNA results and report from Adult Inherited Metabolics- and on the back page, they had photocopied lab results that I was unaware of - one was a 6th MMA test taken a year ago - result was 205 nmol/L, now quite comfortably within range (0-280) for the first time.

So previous 350-400 was never "my normal" at all. It just took 3 years to get there, instead of 3 days !