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| 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
Patient Preparation
Minimum Volume
1.1 mL
Other Acceptable Specimens
Plasma collected in a sodium heparin (green-top) tube
Instructions
Red-top tubes (preferred): 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 (acceptable): 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 (acceptable): 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 (acceptable): 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 (acceptable): 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 • Unseparated serum or plasma • Whole blood samples • Grossly lipemic
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 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
| Methylmalonic Acid | 87-318 nmol/L |
| Homocysteine | |
| Male | <11.4 umol/L |
| Female | <10.4 umol/L |
Clinical Significance
To diagnose and monitor vitamin B12 (cobalamin) deficiency.
