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Test ID: Vit.B12
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Vitamin B12
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Useful For
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To diagnose Megaloblastic anemia and to monitor the effectiveness of treatment for vitamin B12 or folate deficiency.
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Method name and description
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Electrochemiluminescence immunoassay (ECLIA): Competetion principle
Patient specimen with vitamin B12 pretreatment 1 and pretreatment 2 is incubated to release bound B12. Pretreated sample with ruthenium‑labeled intrinsic factor form a vitamin B12‑binding protein complex. After addition of streptavidin-coated microparticles and vitamin B12 labeled with biotin, the still-vacant sites of the ruthenium‑labeled intrinsic factor become occupied, with formation of aruthenium‑labeled intrinsic factor vitamin B12 biotin complex and the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined via a calibration curve which is instrument specifically generated by 2‑point calibration and a master curve.
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Clinical information
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Vitamin B12, also referred to as cobalamin, is a water-soluble vitamin mainly found in foods such as red meat, fish, poultry, milk, yogurt, and eggs. It is necessary for normal red blood cell (RBC) formation, repair of tissues and cells, and synthesis of DNA, the genetic material in cells. Vitamin B12 deficiency impacts red blood cell synthesis, resulting in megaloblastic anemia due to abnormal DNA synthesis, impairs neurological function; in particular demyelination of nerves in part due to abnormal methylation, leading to peripheral neuropathy, dementia, poor cognitive performance, and depression. Other effects of vitamin B12 deficiency or depletion are increased risk of neural tube defects, osteoporosis, cerebrovascular and cardiovascular diseases. Early diagnosis is essential, because of the latent nature of this disorder and the risk of permanent neurological damage.
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum, Plasma
Minimum volume of sample: 1 mL
Serum: Plain tube (red or yellow top)
Plasma: Li‑heparin tube
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Collection instructions / Special Precautions / Timing of collection
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Collect blood by standard venipuncture techniques as per specimen requirements. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
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Storage and transport instructions
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Storage: 48 days at 2 – 8°C
2 hours at 15 – 25°C
56 days at ‑20 °C (± 5 °C)
Transport: 2-25°C
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Specimen Rejection Criteria
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Grossly hemolyzed, icteric and lipemic samples, wrong collection container, insufficient sample and heat‑inactivated samples
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Biological reference intervals and clinical decision values
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Age
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Male (pmol/L)
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Female (pmol/L)
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0-1 Year
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216 - 891
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168-1117
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1-3 Years
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195 -897
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307 - 892
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3-6 Years
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181 -795
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231-1038
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6-9Years
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200 -863
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182 -866
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9-12 Years
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135 -803
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145 - 752
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12-18 Years
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158 -638
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134 - 605
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>18 Years
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145 - 569
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145 - 569
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Turnaround time / Days and times test performed / Specimen retention time
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Daily (24/7)
Turn-around time:
Routine: One working day
Specimen Retention: 4 days
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