Methylmalonic acid (serum)

Referred to Berkshire & Surrey Pathology Services, Frimley Park Hospital NHS Foundation Trust, Portsmouth Road, Frimley, Surrey GU16 7UJ

Alternative names, keywords


Samples required

Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples.

Test indications

Suspected B12 deficiency.

Reference range

In the context of a raised total homocysteine and the absence of renal impairment, increased concentrations of both fasting plasma homocysteine and methylmalonic acid are compatible with B12 deficiency. If both are normal, then B12 deficiency is unlikely; if only plasma homocysteine is increased, then folate deficiency is possible.

< 0.29 µmol/L

considered NOT indicative of B12 deficiency.

0.29 - 0.70 µmol/L

suggests B12 deficiency.

> 0.70 µmol/L

consistent with overt B12 deficiency.


Turnaround time

Referral lab quotes turnaround time of 10 days, however additional time must be allowed for packing, dispatch and delivery of sample, and return and processing of results.


Biochemistry (Referrals)