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Test Code VITB12 Vitamin B12, LAB67


Chemiluminescence/Competitive Binding Immunoenzymatic Assay

Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements

Specimen must be drawn prior to any blood transfusions.

 Do not use samples that have been stored at room temperature for longer than 8 hours.  After centrifugation, store separated samples at 2 - 8 ° C.  Samples must be tested within 48 hours of collection.  If samples cannot be tested within the above timeframe, samples should be separated and frozen at -20° C.



Preferred: Green-top (lithium heparin) tube Hemolyzed specimen is not acceptable.

Acceptable: Gold-top serum gel tube, plain red-top tube, or lavender-top (EDTA) plasma

Specimen: 0.2 mL of plasma or serum

Stability: Samples should be separated from cells as soon as possible with a maximum

                 limit of 2 hours.  Specimens are stable for 24 hours at room temperature or kept

                 at 2 – 8 °C and analyzed within 48 hours. For longer storage, samples may be

                 frozen at -20 °.  Protect samples from light. Avoid using hemolyzed samples.

Collection Instructions: Fasting specimen is preferred. Forward promptly. If there is a delay

                  in transport of >24 hours or if mailing time exceeds 24 hours, send specimen

                  frozen in plastic vial.  

Note: 1. Human anti-mouse antibodies or other heterophile antibodies may be present in patient specimens. This assay has been specially formulated to minimize the effects of these antibodies, however results from patients known to have these antibodies should be carefully evaluated.

2.  This assay is affected by biotin interference.


Reference Values

211-911 pg/mL

Day(s) Test Set Up

Monday through Friday

Test Classification and CPT Coding


Useful For

Early diagnosis of B12 deficiency is crucial because of the latent nature of this disorder and the risk of irreversible neurological damage. Recent studies suggest that in addition to serum B12 levels, folic acid, methylmalonic acid and homocysteine should be measured to improve the specificity of the diagnosis.


Elevated B12 levels are seen in hematological disorders (chronic myelogenous leukemia, promyelocytic leukemia, polycythemia vera) and in liver disorders (acute hepatitis, cirrhosis, hepatocellular carcinoma).