Help with converting MMA result - Pernicious Anaemi...

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Help with converting MMA result

AmelieV12
AmelieV12

Hi,

I just got the test result for methylmalonic acid in urine:

Creatinine: 1.78 g/l

MMA: 2.6 mg/g creatinine

Since I only see MMA mentioned in nmol/l everywhere, I was wondering if I could convert it to that: 2.6 mg/g * 1.78 g/l = 4.6 mg/l MMA. The molecular weight of MMA is 118.091 g/mol, so 0.0046g/(118.091g/mol) ≈ 3.8*10^-5 mol = 38000 nmol. So my MMA would be 38000 nmol/l, which is obviously wrong. Is it even meaningful to convert from mg/g creatine to nmol/l?

5 Replies

You have 1.78 g of creatinine per L. Which seems high for blood. So I suspect this is a urine test.

The urine test has a reference value of <3.60 mmol/mol creatinine

mayomedicallaboratories.com...

MMA has a relative molecular mass of 104 g/mol. Creatinine has a RMM of 113 g/mol

So your 1.78 g of creatinine = 0.016 mol = 16 mmol

You have 2.6 x 1.78 = 4.6 mg of MMA which = 0.045 mmol. 2.6mg/g x 1.78 g

So your MMA level is 0.002 mmol (MMA) / mol (Creatinine) 0.045 mmol / 16 mol.

Well within limits.

AmelieV12
AmelieV12 in reply to fbirder

Hi, thanks for the explanation. Are you sure you're calculating mmol/mol and not mmol/mmol? Because the creatine is 0.016 mol, so you'd get 0.045mmol/0.016 mol = 2.8mmol/mol right? Still within range.

fbirder
fbirder in reply to AmelieV12

D'oh!

Yes you are right. I thought that seemed a bit low.

Also, is taking B12 pointless with these values? My B12 was 152 pmol/l so I felt like I should be taking extra B12 since I believed I was getting some symptoms, but with these MMA results I guess there's no need? I also have low B6 (18nmol/l, should be 30+) and somewhat low folate (9.1 nmol/l).

fbirder
fbirder in reply to AmelieV12

I would try taking some oral B12.

With you low B6 and folate a multi-B Vitamin pill might be a good idea. Tesco do a good, cheap, one with the right amounts (no silly overkill).

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