Clinics and Departments

Laboratory Services

Lab Dept:

Urine/Stool

Test Name:

METHYLMALONIC ACID (MMA), URINE

General Information

Lab Order Codes:

MMAU

Synonyms:

MMA, Urine

CPT Codes:

83921 – Organic acid, single, quantitative

Test Includes:

Quantitative MMA level reported in umol/L.

Logistics

Test Indications:

Evaluating children with signs and symptoms of methylmalonic Acidemia. Screening for the differential diagnosis of signs and symptoms associated with a variety of causes of cobalamin deficiency. Serum MMA may be a more reliable marker of cobalamin deficiency than direct cobalamin determination.

Lab Testing Sections:

Chemistry - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: MMAU/80290)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

3 - 5 days, performed Monday - Friday

Special Instructions:

Overnight fast recommended prior to specimen collection. See Collection.

Specimen

Specimen Type:

Random urine

Container:

Urine container

Draw Volume:

4 mL (Minimum: 1.2 mL) second-voided urine

Processed Volume:

Same as Draw Volume

Collection:

Second-voided urine specimen after an overnight fast.

Special Processing:

Lab Staff: Send urine specimen aliquot frozen in a plastic, 13 mL urine tube. Forward promptly.

Patient Preparation:

Second-voided urine specimen after an overnight fast.

Sample Rejection:

Warm specimen; specimens other than urine

Interpretive

Reference Range:

<3.60 mmol/mol creatinine

In pediatric patients, markedly elevated MMA values are consistent with a diagnosis of methylmalonic acidemia.

In adults, moderately elevated MMA values indicate a likely cobalamin deficiency.

Critical Values:

N/A

Limitations:

Diet, nutritional status, and age should be considered in the evaluation of serum MMA level.

Methodology:

Liquid chromatography-tandem mass spectrometry stable isotope dilution analysis (LC-MS/MS).

References:

Mayo Medical Laboratories May 2013



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