Vitamin B12
- Description
- The Architect B12 assay is a chemiluminescent microparticle intrinsic factor for the quantitative determination of vitamin B12 in human serum or plasma Due to the relocation of the Nutristasis service to the Blackfriars Hub site, this test is not currently accredited by UKAS to ISO15189
- Clinical details
- Vitamin B12 (cobalamin), a member of the corrin family, is a cofactor for the conversion of methylmalonyl Coenzyme-A (CoA) to succinnyl CoA. In addition, vitamin B12 is a cofactor in the synthesis of methionine from homocysteine, is implicated in the formation of myelin, and, together with folate, is required for DNA synthesis. Impaired vitamin B12 status, which may lead to clinical deficiency, is common in mixed patient populations, especially in those older than 60 years. Vitamin B12 deficiency can occur in patients with autoimmune disease (pernicious anaemia), severe primary hypothyroidism, those with ileal disease, patients on chronic therapy with antacids, proton pump inhibitor or H2 antagonists, or colchicine, and in chronic malnutrition states including alcoholism. Common causes also include adherence to vegetarian and vegan diets. A serum B12 test measures all cobalamins - holoTC (20-30%) and B12-haptocorrins (70-80%). Values below the normal expected range (except for pregnancy and congenital haptocorrin deficiency) may indicate that tissue B12 stores are becoming depleted. However, a B12 level in the low-normal range does not ensure that vitamin B12 levels are sufficient and patients may require further evaluation with other tests e.g. Active B12 (holoTC), homocysteine and methylmalonic acid.
- Related condition
- Reference range
Age and ethnicity reference ranges for serum B12
- 0 – 1 yr old 215 – 1389 ng/L
- 2 - 5 yr 374 – 1494 ng/L
- 6 – 9 yr 332 -1081 ng/L
- 10 – 13 yr 253 – 871 ng/L
- >14 yr 225 – 1091 ng/L (Black and Black British ethnic group)
- > 14 yr 182 – 692 ng/L (White and Asian ethnic group)
For pregnancy, trimester specific serum B12 reference ranges apply:
- First trimester 168-574 ng/L, Second trimester 154-516 ng/L, Third trimester 112-465 ng/L
- Units
- ng/L
- Synonyms
- total B12, cobalamin/vitamin B12 deficiency, pernicious anaemia, haptocorrin deficiency
- Testing site
- Synnovis : Reference Services : Blackfriars Hub
- Laboratory
- Nutristasis Unit
- Sample type and volume required
- SST
- Call in advance
- No
- Storage and transport
- separated serum can be sent by first class post
- Turnaround time
- Samples processed daily between Mon-Friday (9am-5pm).
- Contacts
Nutristasis Unit at Blackfriars Hub
Phone: 0204 591 0055
Email: Nutristasis@synnovis.co.uk
Nutristasis
Floor 1, Synnovis Hub
Friars Bridge Court
41-43 Blackfriars Road
London
SE1 8NZ