B12 contains a mineral, cobalamin, and is sometimes referred to as cyancobalamin. The test is run on serum, usually in conjunction with folate (folic acid). B12 is a water-soluble vitamin. It is necessary for DNA and red blood cell synthesis, new cell growth, maintenance of nervous tissue and glucose metabolism. It is also one of the vitamins (along with B6 and folate) essential to convert homocysteine back to methionine. Decreased levels can cause anemia (pernicious anemia), fatigue, irritability, loss of appetite, labored breathing, constipation, heart palpitations, headache and "sore tongue." Some congenital defects have been linked to low B12 levels.
It is found in liver, oysters, poultry, fish, clams, salmon and eggs. B12 tends to be low in vegans.
The RDA is 2.4 micro grams. A supplemental level is 3 to 1000 micrograms. There is no toxic dose listed for B12.
Specimen required is 1.0 mL of serum, protected from light.
Doctors who wish to order kits, please call our lab directly to set up an account before ordering. 316-684-7784
- Allen R: Megaloblastic anemias, in Wyngaarden JB, et al. Editors, 1992; Cecil Textbook of Medicine, Philadelphia, W.B. Saunders Co., 19th ED:847-856
- Beuerlein F: Testing strategies for anemias. 1988; Lab Manag; December: 23-28.
- Herbert V: The five possible causes of all nutrient deficiencies: illustrated by deficiencies of vitamin B12 and folic acid; 1973; Am J Clin Nutr; 26:77-78.
- CPT CODE:
- COLLECTION CONTAINER:
- SST or red-stopper tube
- STATE & SHIPPING RESTRICTIONS:
- We cannot ship lab kits to NY, AK, HI, or international
- MINIMUM VOLUME:
- 0.2 mL
- NORMAL VALUES:
- The normal value established in our laboratory for B12 is 165 to 1100 pg/mL.
- PATIENT PREP:
- PROCESS METHOD:
- The methodology is an RIA method using a 57CO as a label and is performed on serum or plasma.
- PROCESS TIME:
- 5 to 7 business days
- REJECTION CAUSES:
- SPECIMEN VOLUME:
- 1 mL serum; light protected
- TRANSPORT CONTAINER:
- Amber plastic transport tube
- TRANSPORT INSTRUCTIONS:
- Refrigerate or freeze