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Vitamin B12

Item Value
Test Update Information Method changed from Siemens Centaur XP platform to Abbott Architect i2000 platform on 11/13/2017. The Abbott Architect method reads approximately 14% higher than the Centaur method. Please note that the reference ranges have changed.

Abbott manufacturers B12 internal standards gravimetrically using Cyoanocobalamin (USP Reference Standard). The B12 calibrators are manufacturered and tested against these internal standards.

Clinical Questions Does my patient have anemia due to a nutritional deficiency?
Approval req'd? No
Available Stat? No
Test code VB12
Performed by China Basin Chemistry
In House Availability Wednesday, Sunday (day shift)
Method Chemiluminescent Microparticle Immunoassay (Abbott Architect i2000)
Container type Gold top or Red top
Amount to Collect 1 mL blood
Sample type Serum
Preferred volume 0.3 mL serum
Min. Volume 0.15 mL serum
Processing notes Aliquot and freeze serum at -20C.
Units ng/L
Normal range Adult Reference Range (≥18 years):

Adult Reference Range
301-816 ng/L NORMAL. Deficiency unlikely (sensitivity of approximately 90%; however, the assay may not be as sensitive in individuals with anti-intrinsic factor [IF] antibodies).
200-300 ng/L BORDERLINE. Additional testing may be indicated depending on the clinical circumstances.
< 200 ng/L LOW. Consistent with deficiency. Additional testing may be indicated to determine the accuracy of the diagnosis and possibly its cause.

Adult reference range adopted from https://www.uptodate.com and vendor package insert. Verified in-house with lab donor samples.

Pediatric Reference Range:

Pediatric Reference Range
Age Range (ng/L)
5 days - < 1 year 259 - 1576
1 year - < 9 years 283 - 1613
9 years - < 14 years 252 - 1125
14 years - < 17 years 244 - 888
17 years 203 - 812

Pediatric reference ranges adopted from CALIPER Pediatric Reference Interval study performed on random samples using the Abbott Architect i2000 assay.
Synonyms Cobalamin
Stability Room Temperature: 3 days
Refrigerated (2-8°C): 7 days

Avoid more than 3 freeze-thaw cycles.
Turn around times 1-5 days
Additional information To convert ng/L to pmol/L (SI units) multiply by 0.738.

Cobalamin in the plasma and cytosol is bound to several proteins, including intrinsic factor, transcobalamins I and II and haptocorrin. Biologically active cobalamin is carried by intrinsic factor in the gut and by transcobalamin II in plasma. Changes in the other binding proteins ("R proteins"), can alter total cobalamin without affecting normal biological activity. Similarly, some patients may be deficient in biologically active forms of cobalamin despite "normal" or borderline low total cobalamin. If the measured cobalamin level is inconsistent with the clinical presentation, additional testing for increased serum levels of methylmalonic acid may be helpful in confirming or rejecting a diagnosis of B12-deficiency in individuals with normal or borderline low levels of cobalamin.
CPT coding 82607
LOINC code 2132-9
Last Updated 12/1/2017 12:18:54 PM
Entry Number 1000
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