Clinics and Departments

Laboratory Services

Lab Dept:

Chemistry

Test Name:

VITAMIN B12 ASSAY

General Information

Lab Order Codes:

VB12

Synonyms:

B12; Vit B12; Cyanocobalamin

CPT Codes:

82607 – Cyanocobalamin (Vitamin B12)

Test Includes:

Vitamin B 12 level reported in ng/L.

Logistics

Test Indications:

Useful in detecting vitamin B12 deficiency anemia. Helps diagnose the cause of anemia, especially when the RBC’s are described as macrocytic in non-neonates.

Lab Testing Sections:

Chemistry - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: B12/9154)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1 - 2 days

Special Instructions:

N/A

Specimen

Specimen Type:

Whole blood

Container:

Red top tube

Draw Volume:

2 mL (Minimum: 1.5 mL) blood

Processed Volume:

0.6 mL (Minimum: 0.5 mL) serum

Collection:

Routine venipuncture

Special Processing:

Lab Staff: Centrifuge specimen. Separate and transfer serum into screw-capped plastic vial. Store and ship at refrigerated temperatures. Forward promptly.

Patient Preparation:

None

Sample Rejection:

Specimens other than serum; moderate hemolysis; warm specimens, mislabeled or unlabeled specimens

Interpretive

Reference Range:

All ages: 180 - 914 ng/L

Critical Values:

N/A

Limitations:

Patients taking Vitamin B 12 supplementation may have misleading results.

Many other conditions are known to cause an increase or decrease in the serum vitamin B 12 concentration including: Increases: Ingestion of vitamin C, ingestion of estrogens, ingestion of vitamin A, hepatocellular injury, myeloproliferative disorder, uremia. Decreases: Pregnancy, aspirin, anticonvulsants, colchicine, ethanol ingestion, contraceptive hormones, smoking, hemodialysis, multiple myeloma.

The evaluation of macrocytic anemia requires measurement of both vitamin B 12 and folate levels; ideally they should be measured simultaneously.

Some patients who have been exposed to animal antigens either in the environment or as part of treatment or imaging procedure, may have circulating antianimal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results.

Methodology:

Immunoenzymatic assay

References:

Mayo Medical Laboratories Web Page (September 2006)



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