Cobalamin, Methionine, and Methylmalonic Acid Pathways, Serum
Use
This test is useful for screening and monitoring patients suspected of or confirmed with an inherited disorder of methionine, cobalamin, or propionate metabolism using serum specimens. It also helps evaluate individuals with suspected deficiency of vitamin B12. The test measures levels of key metabolites like homocysteine, methylmalonic acid (MMA), methylcitric acid, methionine, cysteine, and cystathionine, providing valuable insight into the pathways involved in methionine, cobalamin, and propionate metabolism.
Special Instructions
Patient's age and sex are required. A Biochemical Genetics Patient Information form should be submitted with the specimen. If not ordering electronically, a Biochemical Genetics Test Request form must be completed and sent with the specimen.
Limitations
The test may not differentiate between inherited defects of enzymes involved in MMA metabolism and acquired deficiencies of vitamin B12. Conditions like kidney insufficiency, hypovolemia, or bacterial overgrowth may also cause mild methylmalonic acidemia. It may also not distinguish perfectly between vitamin B12 and folate deficiency states without additional testing.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.4 mL
Container
Plastic vial
Collection Instructions
Within 4 hours of collection, centrifuge and aliquot serum into plastic vial.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 28 days |
| Refrigerated | 28 days |
| Frozen | 309 days |