Vitamin B12 and Folate, Serum
Use
This test is useful for the investigation of macrocytic anemia, the workup of deficiencies seen in megaloblastic anemias, and the investigation of suspected folate deficiency. It is also employed in diagnosing neuropathy associated with vitamin B12 deficiency. Evaluation of macrocytic anemias typically requires measurement of both serum vitamin B12 and folate at the same time.
Special Instructions
Fasting for 8 hours is required before specimen collection. Do not order on patients who have recently received methotrexate or other folic acid antagonists. For optimal results, ensure proper centrifugation and aliquoting of serum into a plastic vial promptly after collection.
Limitations
Patients taking vitamin B12 supplementation, or those exposed to animal antigens, may exhibit misleading results due to interfering antibodies. Improper specimen storage or handling can also adversely affect test outcomes. Serum folate tests may show false normal or elevated results shortly after folic acid intake, potentially masking deficiencies.
FDA ApprovedNew York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 96805-7
- 2132-9
- 2284-8
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial.
Patient Preparation
Fasting: 8 hours, required
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 7 days |
| Frozen | 90 days |