Minimum of 1.0 mL serum; alternately 1.0 mL serum from Red Top tube
Supplies for Submission
SST/Gold Top (1); alternately Red Top (1)
Specimen Collection
Label serum separator tube (SST) with two identifiers. Acceptable identifiers include patient’s name, date of birth, social security number, requisition number, and medical record number.
Store on ice until separation. Allow SST contents to clot in an upright position for at least 30 minutes (60 minutes for Red Top tube).
SST specimen - centrifuge within 1 hour of collection and refrigerate.
Red Top specimen - centrifuge within 2 hours of collection, transfer serum to a plastic transport tube labelled appropriately and as Red Top serum, and refrigerate.
Storage Requirements
Refrigerated. Specimens are stable if refrigerated for 1 week or frozen for 1 month.
Turn Around Time
8 days
Limitations
Patients who are taking methotrexate, carbamazepine, phenytoin, nitrous oxide, anticonvulsants, or 6-azuridine triacetate may have higher levels of homocysteine due to metabolic interference.