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Test Code:
090-31-4004

Order Name:
Methylmalonic Acid (MMA), Quantitative, Serum **

 
Useful For:

Evaluating children with signs and symptoms of methylmalonic acidemia
Evaluating individuals with signs and symptoms associated with a variety of causes of cobalamin (vitamin B12) deficiency

 
Methodology:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
 
AliasesName:
B12 Deficiency
CblC
Cobalamin Deficiency
Methylmalonate
Methylmalonic Acid (MMA)
MMA (Methylmalonic Acid)
Methylmalonic Aciduria
 
 
 
Test Code:
090-31-4004

Order Name:
Methylmalonic Acid (MMA), Quantitative, Serum **

 
Patient Preparation:
N/A
 
Collection Specimen Or Container:
Blood/ Plain blood (Red top) 6 mL, 2 tubes
 
 
Specimen Testing Type:
Serum, minimum volume 1 mL x 2 tubes
 
 
Sub Mission Container:
Plastic tube
 
Rejection Criteria:
N/A
 
Specimen Stabillity:
Specimen Type Temperature Time
Serum
Refrigerated (preferred) 48 days
Frozen  48 days
Ambient  48 days
 
 
 
Test Code:
090-31-4004

Order Name:
Methylmalonic Acid (MMA), Quantitative, Serum **

 
Method detail:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
 
Schedule:
N/A **Sent out to MAYO, USA
 
Turnaround Time:
Received specimen to reported within 14 days
(exception for official holidays)
 
Performing Location:
MAYO Laboratory
Referral Lab Services, Laboratory Department 14160-2
 
 
 
Test Code:
090-31-4004

Order Name:
Methylmalonic Acid (MMA), Quantitative, Serum **

 
 
Clinical Information:

Elevated levels of methylmalonic acid (MMA) result from inherited defects of enzymes involved in MMA metabolism or inherited or acquired deficiencies of vitamin B12 (cobalamin) or its downstream metabolites. Acquired nutritional deficiencies are much more common than inherited defects and can be due to intestinal malabsorption, impaired digestion, or poor diet. Elderly patients with cobalamin deficiency may present with peripheral neuropathy, ataxia, loss of position and vibration senses, memory impairment, depression, and dementia in the absence of anemia. Other conditions such as renal insufficiency, hypovolemia, and bacterial overgrowth of the small intestine also contribute to the possible causes of mild methylmalonic acidemia and aciduria.

MMA is also a specific diagnostic marker for the group of disorders collectively called methylmalonic acidemia, which include at least 7 different complementation groups. Two of them (mut0 and mut-) reflect deficiencies of the apoenzyme portion of the enzyme methylmalonyl-CoA mutase. Two other disorders (CblA and CblB) are associated with abnormalities of the adenosylcobalamin synthesis pathway. CblC, CblD, and CblF deficiencies lead to impaired synthesis of both adenosyl- and methylcobalamin.

Since the first reports of this disorder in 1967, thousands of cases have been diagnosed worldwide. Newborn screening identifies approximately 1 in 30,000 live births with a methylmalonic acidemia. The most frequent clinical manifestations are neonatal or infantile metabolic ketoacidosis, failure to thrive, and developmental delay. Excessive protein intake may cause life-threatening episodes of metabolic decompensation and remains a lifelong risk unless treatment is closely monitored, including serum and urine MMA levels.

Several studies have suggested that the determination of serum or urinary methylmalonic acid could be a more reliable marker of cobalamin deficiency than direct cobalamin determination.

 
Reference Value:

< or =0.40 nmol/mL

 
Interpretation:

In pediatric patients, markedly elevated methylmalonic acid values indicate a probable diagnosis of methylmalonic acidemia. Additional confirmatory testing must be performed.
In adults, moderately elevated values indicate a likely cobalamin (vitamin B12) deficiency.

Cautions 
Diet, nutritional status, and age should be considered in the evaluation of serum or urine methylmalonic acid level.

 
Clinical Reference:
www.mayocliniclabs.com (Retrieved: 21 July 2020)