Methylmalonic Acid

Test Code
34879

CPT Codes
83921

Preferred Specimen
2 mL serum

Minimum Volume
1 mL

Other Acceptable Specimens
Serum collected in: No additive (royal blue-top) tube • Plasma collected in: Sodium heparin (green-top) or sodium heparin (royal-blue-top) tube

Transport Container
Plastic screw-cap vial

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 10 months

Methodology
Mass Spectrometry (MS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Mon-Sat; Report available: 2 days

Reference Range
87-318 nmol/L

Clinical Significance
The Methylmalonic Acid (MMA) test is used in the diagnosis of acquired cobalamin (vitamin B12) deficiency in adults and to screen for inherited organic acidemia in neonates and infants. Elevated MMA in either blood or urine indicates vitamin B12 deficiency in adults, with MMA acting as a functional biomarker for vitamin B12 status. In neonates and infants, elevated MMA is associated with inborn errors of metabolism [1].

Adults with signs and symptoms of cobalamin deficiency, including peripheral neuropathy, ataxia, memory impairment, depression, behavioral changes, and anemia, should be tested for MMA, especially if they are elderly or have experienced intestinal malabsorption or digestive disorders [1]. In the United States all newborns should be screened for MMA as part of the Department of Health and Human Services (HHS) Recommended Universal Newborn Screening Panel [2].

MMA can be acquired due to underlying medical conditions that lead to B-vitamin deficiencies or inherited as an autosomal recessive inborn error of metabolism. If a neonate or infant has elevated MMA suggestive of an organic acidemia, the parents may elect to undergo carrier testing, or have their other children undergo genetic testing. Siblings of a child with MMA-related mutation have a 25% chance of being affected and a 50% chance of being a carrier [3].

References
1. AACC. Methylmalonic acid. Updated May 10, 2019.
https://labtestsonline.org/tests/methylmalonic-acid. Accessed July 20, 2019.
2. Department of Health and Human Services. Recommended Uniform Screening Panel. https://www.hrsa.gov/advisory-committees/heritable-disorders/rusp/index.html. Updated February 2019. Accessed July 2019.
3. Manoli, et al. Isolated methylmalonic academia. Updated: December 1, 2016. In: Adam MP, Ardinger HH, Pagon RA, et al. editors. GeneReviews [Internet]. Seattle (WA)L University of Washington

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Dr
Chantilly, VA 20153



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.