Vitamin B12 & Folate

Test Code

B12FO

Alias/See Also

Epic: LAB2496

Preferred Specimen

Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL

Minimum Volume

0.2 mL

Instructions

Centrifuge and separate cells after clot formation and within 4 hours of collection. Remove serum if testing will be delayed more than 24 hours.
For accurate results, serum specimens should be free of fibrin, red blood cells, and other particulate matter. Do not use grossly hemolyzed specimens. Specimens with obvious microbial contamination should not be used.
Serum specimens to be tested for folate should be protected from light.Centrifuge to separate from cells as soon as possible. Avoid more than 3 freeze-thaw cycles.

Transport Container

Plastic vial

Transport Temperature

Refrigerated

Specimen Stability

Room temperature: Undefined
Refrigerated (on gel): 24 hours
Refrigerated (off gel): 7 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Samples stored on gel >24 hours, unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.

Methodology

Chemiluminescent Microparticle Immunoassay (CMIA)

Setup Schedule

Daily

Report Available

Same day

Limitations

Hemolyzed specimens will give falsely elevated folate levels.

Folate samples should be protected from light.

Accumulation of denatured protein from the pre-treatment step in the sample probe may impact other assays on the ARCHITECT. Daily maintenance procedure 6041 must be run to eliminate this effect.

Specimens containing human anti-mouse antibodies (HAMA) may show either falsely elevated or depressed values when tested. Heterophilic antibodies in human serum can react with reagent immunoglobulins, interfering with in vitro assays. Patients routinely exposed to animals or animal serum products can be prone to this interference, and anomalous values may be observed. Serum or plasma from patients with renal impairment or failure may exhibit varying degrees of falsely depressed folate values. Methotrexate, aminopterin, and folinic acid (Leucovorin) are chemotherapeutic agents whose molecular structures are similar to folate, and can cross react with folate binding protein. Do not use the ARCHITECT Folate assay for patients using these drugs.

Reference Range

Folate deficiency: <3.5 ng/mL
Indeterminate folate: 3.5 – 5.4 ng/mL
Normal folate: >5.4 ng/mL

Performing Laboratory

Inova Laboratories

2832 Juniper Street

Fairfax, VA 22031

Last Updated: March 10, 2023
Last Review: N. Wolford, March 10, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.