|
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Methylmalonic Acid and Homocysteine
Test Code30517
CPT Codes
83090, 83921
Preferred Specimen
2.7 mL serum
Minimum Volume
1.1 mL
Other Acceptable Specimens
Plasma collected in: Sodium heparin (green-top)
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.
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
Refrigerated: 7 days
Frozen: 6 months
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Grossly lipemic • Unseparated serum or plasma • Whole blood
Methodology
Methylmalonic Acid: Tandem Mass Spectrometry • Homocysteine: Enzymatic
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 FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes
Setup Schedule
Set up: Mon-Sat; Report available: 4-5 days
Reference Range
Methylmalonic Acid
Homocysteine
| ≤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 |
Clinical Significance
To diagnose and monitor vitamin B12 (cobalamin) deficiency.
