Test Catalog

Test Id : B12

Vitamin B12 Assay, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Investigation of macrocytic anemia

 

Workup of deficiencies seen in megaloblastic anemias

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Immunoenzymatic Assay

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Vitamin B12 Assay, S

Aliases
Lists additional common names for a test, as an aid in searching

CblC

Cobalamin

Cobalamin Cyanocobalamin

Cobalamin Deficiency

Cyanocobalamin

Vitamin B12 and Folate, Serum

Vitamin B12, Serum

B(12) Assay

B12 Assay

B12, Serum

Vitamin B-12 Assay, Serum

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Specimen Type
Describes the specimen type validated for testing

Serum

Ordering Guidance

Ask patients if they have received a vitamin B12 injection or radiolabeled vitamin B12 injection within the last 2 weeks. Patient results will not reflect deficiency or malabsorption after recent B12 injection. If patient has received such an injection within the past 2 weeks, this test should not be ordered.

 

This test provides a measurement of serum vitamin B12 level only. For a more comprehensive workup, order ACASM / Pernicious Anemia Cascade, Serum, which initiates testing with measurement of vitamin B12. Depending of the vitamin B12 concentration, testing for intrinsic factor blocking antibody, gastrin, and methylmalonic acid may be added.

Necessary Information

Ask patients if they have received a vitamin B12 injection within the last 2 weeks. Patient results will not reflect deficiency or malabsorption after recent B12 injection. If patient has received an injection within the past 2 weeks, this test should not be ordered.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Patient Preparation: This test should not be performed on patients who have received a vitamin B12 injection or radiolabeled vitamin B12 injection within the previous 2 weeks.

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.6 mL

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and the serum aliquoted into a plastic vial within 2 hours of collection.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
Frozen 90 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Investigation of macrocytic anemia

 

Workup of deficiencies seen in megaloblastic anemias

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Vitamin B12 (cobalamin) is necessary for hematopoiesis and normal neuronal function. In humans, it is obtained only from animal proteins and requires intrinsic factor (IF) for absorption. The body uses its vitamin B12 stores very economically, reabsorbing vitamin B12 from the ileum and returning it to the liver; very little is excreted.

 

Vitamin B12 deficiency may be due to lack of IF secretion by gastric mucosa (eg, gastrectomy, gastric atrophy) or intestinal malabsorption (eg, ileal resection, small intestinal diseases).

 

Vitamin B12 deficiency frequently causes macrocytic anemia, glossitis, peripheral neuropathy, weakness, hyperreflexia, ataxia, loss of proprioception, poor coordination, and affective behavioral changes. These manifestations may occur in any combination; many patients have the neurologic defects without macrocytic anemia.

 

Pernicious anemia is a macrocytic anemia caused by vitamin B12 deficiency that is due to a lack of IF secretion by gastric mucosa.

 

Serum methylmalonic acid and homocysteine levels are also elevated in vitamin B12 deficiency states.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

180-914 ng/L

Interpretation
Provides information to assist in interpretation of the test results

A serum vitamin B12 level less than 180 ng/L may cause megaloblastic anemia and peripheral neuropathies.

 

Vitamin B12 levels less than 150 ng/L are considered evidence of vitamin B12 deficiency. Follow-up with a test for antibodies to intrinsic factor (IFBA / Intrinsic Factor Blocking Antibody, Serum) is recommended to identify this potential cause of vitamin B12 malabsorption. For specimens without antibodies and the patient is symptomatic, follow-up testing for vitamin B12 tissue deficiency may be indicated. Consider analysis of methylmalonic acid (MMAS / Methylmalonic Acid, Quantitative, Serum) and/or homocysteine (HCYSP / Homocysteine, Total, Plasma).

 

Patients with serum vitamin B12 levels between 150 and 400 ng/L are considered borderline deficient and should be evaluated further by functional tests for vitamin B12 deficiency. Plasma homocysteine measurement (HCYSP / Homocysteine, Total, Plasma) is a good screening test where a normal level effectively excludes vitamin B12 and folate deficiency in an asymptomatic patient. However, the test is not specific, and many situations can cause an increased level. In contrast, an increased serum methylmalonic acid (MMAS / Methylmalonic Acid, Quantitative, Serum) level is more specific for cellular-level B12 deficiency and is not increased by folate deficiency.

 

In patients being evaluated for vitamin B12 deficiency who have intrinsic factor blocking antibodies (IFBA), false elevations of vitamin B12 may occur due to IFBA interference, potentially obscuring a physiological deficiency of vitamin B12. If observed vitamin B12 concentrations are discordant with clinical presentation, measurement of methylmalonic acid (MMAS / Methylmalonic Acid, Quantitative, Serum) should be considered.

 

For more information, see Vitamin B12 Deficiency Evaluation.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Patients who have received a vitamin B12 injection or radiolabeled vitamin B12 injection within the previous 2 weeks may have high serum vitamin B12 levels, which can interfere with this assay leading to falsely elevated results.

 

Many other conditions are known to cause an increase or decrease in the serum vitamin B12 concentration and should be considered in the interpretation of the assay results, including:

 

Increased serum vitamin B12

Decreased serum vitamin B12

Ingestion of vitamin C

Pregnancy

Ingestion of estrogens

Aspirin

Ingestion of vitamin A

Anticonvulsants

Hepatocellular injury

Colchicine

Myeloproliferative disorder

Ethanol ingestion

Uremia

Contraceptive hormones

 

Smoking

 

Hemodialysis

 

Multiple myeloma

 

The evaluation of macrocytic anemia requires measurement of both vitamin B12 and folate levels; ideally, they should be measured simultaneously.

 

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

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Babior BM: The megaloblastic anemias. In: Williams WJ, Beutler E, Lichtman MA et al, eds. Hematology. 5th ed. McGraw-Hill; 1995:471-490

2. Roberts NB, Taylor A, Sodi R: Vitamins and trace elements. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:chap 37

3. Klee GG: Cobalamin and folate evaluation: measurement of methylmalonic acid and homocysteine vs vitamin B12 and folate. Clin Chem. 2000 August;46(8 Pt 2):1277-1283

4. Allen LH, Miller JW, de Groot L, et al. Biomarkers of nutrition for development (BOND): Vitamin B-12 review. J Nutr. 2018;148(suppl_4):1995S–2027S. doi: 10.1093/jn/nxy201

5. Wolffenbuttel BHR, Wouters HJCM, Heiner-Fokkema MR, van der Klauw MM: The many faces of cobalamin (vitamin B12) deficiency. Mayo Clin Proc Innov Qual Outcomes. 2019;3(2):200-214 Published 2019 May 27. doi: 10.1016/j.mayocpiqo.2019.03.002

6. Hannibal L, Lysne V, Bjorke-Monsen AL, et al: Biomarkers and algorithms for the diagnosis of vitamin B12 deficiency [published correction appears in Front Mol Biosci. 2017 Aug 08;4:53]. Front Mol Biosci. 2016;3:27. doi: 10.3389/fmolb.2016.00027

7. Green R, Kinsella LJ: Current concepts in the diagnosis of cobalamin deficiency. Neurology. 1995;45:1435-1440

8. Lahner E, Annibale B: Pernicious anemia: new insights from a gastroenterological point of view. World J Gastroenterol. 2009 Nov 7;15(41):5121-5128

9. Bizzaro N, Antico A: Diagnosis and classification of pernicious anemia. Autoimmun Rev. 2014;13(4-5):565-568

10. Toh BH: Pathophysiology and laboratory diagnosis of pernicious anemia. Immunol Res. 2017;65(1):326-330

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

The instrument used is a Beckman Coulter DXI 800. The Access Vitamin B12 assay is a competitive-binding immunoenzymatic assay. The sample is added to a reaction vessel along with alkaline potassium cyanide and dithiothreitol. This treatment denatures B12 binding proteins and converts all forms of vitamin B12 to the cyanocobalamin form. After neutralization, intrinsic factor-alkaline phosphatase conjugate and paramagnetic particles coated with goat-antimouse IgG:mouse monoclonal anti-intrinsic factor are added to the sample. Vitamin B12 in the sample binds to the intrinsic factor conjugate, preventing the conjugate from binding to the solid phase anti-intrinsic factor. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field, while unbound materials are washed away. A chemiluminescent substrate is added to the vessel, and the light generated by the reaction is measured with a luminometer. The light production is inversely proportional to the concentration of vitamin B12 in the sample. The amount of analyte in the sample is determined by means of a stored, multipoint calibration curve.(Package insert: Access Vitamin B12. Beckman Coulter, Inc; 04/2020)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

2 weeks

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

82607

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
B12 Vitamin B12 Assay, S 2132-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
B12 Vitamin B12 Assay, S 2132-9

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports