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Test Code B12 Vitamin B12

Important Note

This test may be affected by biotin interference. Patients on high dose biotin (5mg/day or more) should not have samples drawn until at least 24 hours after the last biotin administration.

Specimen and Container/Tube

Specimen Type: Plasma

Preferred Specimen: Li-Heparin Mint Green Top

Other Acceptable specimens: Serum/Gold Top, Serum/Red Top

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

  • Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent frozen at -20oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours

Reference Values

Test

Age

Sex

Reference Range

B12

All

All

240 - 900 pg/mL

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

82607

LOINC Codes

2132-9

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room Temperature

2 hours

Refrigerated

24 hours

Frozen

2 months

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Test Components

Vitamin B12

Clinical Indications

Useful as an aid in the investigation of macrocytic anemia and workup of deficiencies seen in megaloblastic anemias.

Methodology

Electrochemiluminescence immunoassay (ECLIA) (Roche Diagnostics)

Additional Information

Results should always be assessed in conjunction with patient's medical history, clinical examination and other
findings.

 

A normal serum concentration of vitamin B12 does not rule out tissue deficiency of vitamin B12. The most sensitive test for vitamin B12 deficiency at the cellular level is the assay for MMA (Methylmalonic Acid). If clinical symptoms suggest deficiency, measurement of MMA and homocysteine should be considered, even if serum vitamin B12 concentrations are normal.

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: Not available as STAT test

Routine Turnaround Time: up to 4 hours

Testing Schedule:  24/7

Synonyms/Keyword Search

Cyanocobalamin, B12

Last Review Date

8/19/2024