Specimen Collection Manual and Test Catalog

2.7 ml serum (preferred) or plasma: minimum 1.1 mL.

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.

Room temperature.

Room temperature: 4 days. Refrigerated: 7 days. Frozen: 6 months.

Gross hemolysis • Unseparated serum or plasma • Whole blood samples • Grossly lipemic

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.

Quest test code 30517 Mma/Homocyst

To diagnose and monitor vitamin B12 (cobalamin) deficiency.