Vitamin B12, Reflexive
Order Code: B12R
Order Form: Laboratory Requisition
Specimen:
Serum
Collection Medium:
Red top tube
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL whole blood in red top tube or THREE microtainers.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
Normal: 243-894 pg/mL Indeterminant: 175-242 pg/mL Deficient: < 174 pg/mL
Comments:
If plasma is sent and Intrinsic Factor Blocking Antiboies (IFBA) is reflexively ordered, the laboratory will call for an additional r ed top tube if IFBA is required. Intrinsic factor antibody automatically analyzed if B12 result is <243 pg/mL. Patient is charged for IFBA result. Please print, complete and submit the Advance Beneficiary Notice (ABN) along with the Laboratory Requisition before shipping the specimen. New analytical immunoassay with different reference ranges instituted 4/24/00 at 10:00.
Test Limitations:
The assay is unaffected by icterus (bilirubin is less than 65 mg/dL), hemolysis (Hb is less than 1.0 g/dL), lipemia (triglycerides is less than 1500 mg/dL) and biotin is less than 50 ng/mL. (criterion: recovery within plus or minus 10% of initial value). In patients receiving therapy with high biotin doses (i.e. is greater than 5 mg/day) no sample should be taken until at least 8 hours after the last biotin administration. No interference was observed from rheumatoid factors up to a concentration of 1500 U/mL. In vitro tests were performed on 54 commonly used pharmaceuticals. No interference with the assay was found. In rare cases interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur. For diagnostic purposes, the vitamin B12 findings should always be assessed in conjunction with the patient's medical history, clinical examination and other findings.
Methodology:
Electrochemiluminescence immunoassay
Instructions:
Centrifuge, remove serum or plasma, aliquot to plastic tube labeled with patient's name and date drawn. Refrigerate and protect from light.
Sample Processing:
Centrifuge within two hours of draw time.
Centrifuge at 3000 RPM for 10 minutes.
Aliquot serum/plasma into screw-capped plastic vial.
Sample Storage:
Refrigerate.
Transport Instructions:
Place requisition into outside pocket of bag.
Place specimen into zip-lock type bag, seal bag.
Place dry ice on top of specimen in styrofoam container.
Dry Ice up to 24 hours.
CPT Code:
82607