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Vitamin B12

VB12, B12

Test Codes

EPIC: LAB67, Beaker: VB12

Department

Toxicology

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)
Contact Laboratory for acceptability of other tube types.

It is recommended that specimen be protected from light.

Physician Office/Draw Specimen Preparation

It is recommended that specimen be protected from light. Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

Moderate to grossly hemolyzed specimens.

In-Lab Processing

It is recommended that specimen be protected from light. Let SST specimens clot 30-60 minutes. Centrifuge SST and Microtainer^® specimens to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Royal Oak Automated Chemistry Laboratory 
Troy Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day. 
Results available within 24 hours after receipt in the Laboratory.

Reference Range

Adult range: 271-1000 pg/mL.

Deficient: Less than 200 pg/mL.
Borderline: 200-270 pg/mL.
Normal: 271-1000 pg/mL.
High: Greater than 1000 pg/mL.

Test Methodology

Chemiluminescence Immunoassay.

Interpretation

A decreased serum Vitamin B₁₂ level may occur in a number of disorders, most of which are due to malabsorption of Vitamin B₁₂ from the small intestine. The most common of these is pernicious anemia in which intrinsic factor production is reduced; this will also occur following total gastrectomy. Disease or resection of the terminal small intestine prevents absorption of Vitamin B₁₂. Although rare, disorders of transcobalamin, can lead to decreased serum Vitamin B₁₂.

Excessive exposure to light may alter Vitamin B₁₂ values.

Clinical Utility

Vitamin B₁₂ deficiency is usually due to malabsorption resulting from: deficiency of intrinsic factor, disease or resection of the terminal small bowel, or utilization of the vitamin by excessive bacterial flora in the gut. It may also occur in strict vegetarians where insufficient Vitamin B₁₂ is present in the diet.

Vitamin B₁₂ deficiency can result in: macrocytic anemia, neuropathy, psychiatric changes, mental impairment (dementia), and infertility.

Since macrocytic anemia often requires measurement of both Vitamin B₁₂ and folate levels it may be more economical and convenient to perform both tests at the same time.

CPT Codes

82607

Contacts

Last Updated

7/21/2024