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Test Code B12FO Vitamin B12 & Folate

Additional Codes

Epic: LAB2496

Specimen Required

Specimen Type: Serum

Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 3.0 mL
Collection 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.

Specimen Minimum Volume

0.2 mL

Specimen Stability

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

Reference Range

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

Rejection Due To

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

Report Available

Same day

Method Name

Chemiluminescent Microparticle Immunoassay (CMIA)


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.

Day(s) Performed


Transport / Storage Conditions


Special Instructions

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.

CPT Codes




Specimen Type


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