Methylmalonic Acid and Homocysteine
Test code
CPT code(s)*
Test resources
Please visit our Clinical Education Center to stay informed on any future publications, webinars, or other education opportunities.
Details
Methodology
Methylmalonic Acid: Mass Spectrometry (MS) • Homocysteine: Enzymatic
Specimen requirements | |
|---|---|
| Patient preparation | None Specified |
| Preferred specimen(s) | 2.7 mL serum |
| Alternative specimen(s) | Plasma collected in: Sodium heparin (green-top) |
| Minimum volume | 1.1 mL |
| Collection instructions | Red-top tubes: Place the specimen in a refrigerator or ice bath for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation has taken place. Transfer the serum to a transport tube. Barrier gel separator tubes: Place the specimen in a refrigerator for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation has taken place. Do not place barrier tubes in an ice bath as freezing may prevent the barrier gel from adequately separating serum from cells. Heparin tubes: Place the specimen in a refrigerator or ice bath until the specimen can be centrifuged. Centrifuge the specimen as soon as possible and transfer the plasma to a transport tube. |
| Transport container | Transport tube |
| Transport temperature | Room temperature |
| Specimen stability | Room temperature: 4 days Refrigerated: 7 days Frozen: 6 months |
| Reject criteria | Gross hemolysis • Grossly lipemic • Unseparated serum or plasma • Whole blood |
Reference Range(s)
Methylmalonic Acid
| ≤30 days | 87-580 nmol/L |
| 31 days-11 months | 62-377 nmol/L |
| 12-23 months | 55-347 nmol/L |
| 2-59 years | 55-335 nmol/L |
| 60-79 years | 69-390 nmol/L |
| ≥80 years | 85-423 nmol/L |
Homocysteine
| Age | Male (umol/L) | Female (umol/L) |
| 0-1 years | Not Established | Not Established |
| 2-9 years | ≤7.6 | ≤7.6 |
| 10-14 years | ≤9.7 | ≤8.4 |
| 15-17 years | ≤11.3 | ≤10.2 |
| 18-29 years | ≤12.9 | ≤10.9 |
| 30-49 years | ≤13.5 | ≤11.0 |
| >49 years | ≤15.2 | ≤13.4 |
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
*The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.
This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.
The tests listed by specialty and category are a select group of tests offered. For a complete list of Quest Diagnostics tests, please adjust the filter options chosen, or refer to our Directory of Services.