Vitamin B12


Analytical Range:
30 - 2000 ng/L

Time Limit for Add on Tests:
2 days

Target Turnaround time:
1 working day

Further Information from LabTestsOnline

Tube Type:
Serum (Gold Top)

North Devon District Hospital (Mon-Fri)

Reference Range:
197 - 771 ng/L

Patient preparation:
If taking supplements which may contain Biotin (Vitamin B7), do not take in the 8 hours prior to blood test - they may contain agents which affect the analysis

Test Usage

Vitamin B12 is necessary for normal red blood cell formation, tissue and cellular repair, and DNA synthesis. The processes work in conjunction with folate. A Vitamin B12 and/or folate deficiency reflects a chronic shortage of one or both of these vitamins. Since the body stores 3-5 years' supply in the liver, deficiencies and their associated symptoms can take months to years to manifest in adults. Infants and children, however, will show signs of deficiency more rapidly as they have not yet established extensive reserves.

Vitamin B12 deficiency is a common cause of megaloblastic anemia, various neuropsychiatric symptoms ranging in severity, and other clinical manifestations. Screening average-risk adults for vitamin B12 deficiency is not recommended. Screening may be warranted in patients with one or more risk factors, such as gastric or small intestine resections, inflammatory bowel disease, use of metformin for more than four months, use of proton pump inhibitors or histamine H2 blockers for more than 12 months, and adults older than 75 years.


Last updated: March 3, 2021