Laboratory Medicine
Test Directory / Vitamin B12
Vitamin B12
Brown clotted serum, gel barrier
| Test | Vitamin B12 |
|---|---|
| Common Abbreviations | B12 |
| Profile | Haematinics |
| Tube type | Brown clotted serum, gel barrier |
| Clinical Indication | Measured to confirm the diagnosis of vitamin B12 deficiency following the identification of anaemia. Clinical and laboratory findings suggestive of B12 deficiency include neurological abnormalities, decreased serum vitamin B12 levels. macrocytic anaemia and increased excretion of methylmalonic acid. |
| Specimen Type | Blood |
| Sample type | Serum |
| Minimum Volume | 0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample. |
| Special Precautions | No special requirements |
| Stability | 24 hours at 20°C, 48 hours at 2 - 8°C and 56 days at -20°C. |
| Turnaround Time | Inpatient: 24 hours Outpatient/ GP: 24 hours |
| Laboratory | York and Scarborough |
| Reference Interval | 197 - 771 ng/L (Quoted by the manufacturer) |
| Limitations | Analysis should not be performed on haemolysed, icteric or lipaemic samples. Roche assay designed to avoid interference from ant-intrinsic factor antibodies. The assay is unaffected by biotin < 205 nmol/L or < 50 ng/mL. No interference was observed from rheumatoid factors up to a concentration of 1500 IU/mL. No interference was observed from IgG < 2.8 g/dL; IgA < 1.6 g/dL; IgM < 1.0 g/dL Samples should not be taken from patients receiving therapy with high biotin doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration. In rare cases, interference due to extremely high titers of antibodies to analyte specific antibodies, streptavidin or ruthenium can occur. In vitro tests were performed on 16 commonly used pharmaceuticals. No interference with the assay was found. Presence of immunoglobulin-vitamin B12 complexes may cause high results. |
| Notes |
