View Related Pages
Vitamin B12
Principle
Vitamin B12 (cobalamin) is essential for normal hematopoiesis and neurologic function. Reduced serum vitamin B12 concentrations may indicate the presence of vitamin B12–dependent anemia, including megaloblastic and pernicious anemia. Elevated vitamin B12 levels have been associated with pregnancy, use of oral contraceptives or multivitamin supplementation, and certain myeloproliferative disorders such as chronic granulocytic leukemia and myelomonocytic leukemia. Elevated vitamin B12 concentrations are not known to cause clinical harm.
Measurement of serum vitamin B12 is intended to identify and monitor vitamin B12 deficiency. Deficiency may result from impaired intrinsic factor secretion leading to reduced absorption (pernicious anemia), gastrectomy, malabsorption due to intestinal resection, or inflammatory or bacterial diseases affecting the small intestine.
Specimen Requirements
Specimen
Collection
Processing
Storage and Transport
Store/transport at 15–30°C for ≤8 hours; 2–8°C for ≤24 hours; freeze at ≤ –20°C if delayed. Avoid repeated freeze–thaw cycles.
Unacceptable Specimens
Hemolyzed or lipemic specimens.
Method
Enhanced Chemiluminescence.
Normal Range
180–914 pg/ml
Turnaround Time
References
- Ardeman S, Chanarin I. Assay of gastric intrinsic factor in the diagnosis of Addisonian pernicious anemia. British Journal of Haematology. 11:305–314; 1965.
- Chanarin I (ed). The Megaloblastic Anaemias. 3rd ed. Oxford: Blackwell Scientific Publications; 1990.
- Chanarin I (ed). The Megaloblastic Anaemias. 2nd ed. Oxford: Blackwell Scientific Publications; 1979.
- Williams JW, et al. Hematology. 3rd ed. Singapore: McGraw-Hill Book Company; 1986.