Vitamin B12 needs to bind to intrinsic factor, a protein produced by the parietal cells lining the stomach in order to facilitate absorption, which occurs in the terminal ileum. It is necessary for normal red cell formation, tissue repair, and for myelin production in nerves. Body stores of vitamin B12 are in the region of 2 – 3 mg, sufficient to last for up to 4 years. Complications of vitamin B12 deficiency become apparent before macrocytic anaemia is diagnosed.
Vitamin B12 (cobalamin) is part of the B complex of vitamins. It is present in meat and animal protein food sources.
Vitamin B12 is a vital component of myelin production in the nervous system. Mild deficiency can lead to neuropathy, whilst extremely severe deficiency can result in irreversible neurological complications such as subacute combined degeneration of the spinal cord. Vitamin B12 can demonstrate a macrocytic anaemia on blood film.
Causes of Deficiency:
Pernicious Anaemia – this is the most common cause of vitamin B12 deficiency. It is an autoimmune disease most commonly occurring in the 45 – 65 year old age group and predominantly in females. It involves gastritis, atrophic changes and loss of normal gastric glands, mucosal architecture, parietal and chief cells, resulting in the absence of gastric acid. This results in a lack of intrinsic factor production needed to bind to vitamin B12 to aid absorption.
- Inadequate intake: strict vegans as no animal sources in their diet
- Malabsorption states ileal resection, intestinal inflammation e.g. Crohn’s Disease
- Post gastrectomy as fewer parietal cells remain to produce intrinsic factor
- Bacterial overgrowth as a result of blind loop syndrome
- Malignant disease requiring radiotherapy causing irradiation of the terminal ileum
- Gut infection (tapeworm)
- Medications – colchicine, neomycin, metformin, anticonvulsants
- Long-term use of PPIs or H2 receptor antagonists which lower available gastric acid
5mL venous serum
In addition to the packaging of samples, the transport/delivery of clinical samples to the laboratory is required to be in adherence to all national regulations for the safe transport of biological materials. Enfer Medical provides a fully compliant logistics service, aligned with clients’ testing requirements.
Prompt transport of specimens:
To ensure prompt testing of samples and release of results within the published test turnaround times, samples should arrive to the laboratory by 18:00. Test turnaround time is measured from receipt of the sample at the laboratory until the time the authorised results are reported to users.
In rare cases specimens may not be suitable for testing on arrival to the laboratory. In that case the sample will be rejected at the receipt stage and the service user will be notified immediately and an explanation as to why the sample could not be processed will be provided. Reasons why samples cannot be processed include but are not limited to:
- Samples received beyond the stability limits and/or not at the correct temperature indicated for each test.
- Incorrect sample type received.
- Leaking samples, sample not received or sample insufficient for analysis as stated below within sample requirements.
- Non-compliant samples or request forms i.e. those missing sample date information, missing sample test request and/or missing sample site/type information.
- Samples received without the necessary patient identifiers.
Quantitative results for Vitamin B12 are reported in numeric value in pg/mL. Please contact us for more information on the reference ranges used at Enfer Medical.
Critical results are communicated in accordance with the Communication of critical results for patients in the community- national laboratory handbook CSP041/2019