University of Iowa
Diagnostic Laboratories
(UIDL) Test Directory

319-384-7212 (local)
1-866-844-2522 (toll free)


Vitamin B12
Order Code: B12
Order Form: Laboratory Requisition
Specimen:
Plasma
Collection Medium:
Plasma separator tube
Alternate
Collection Media:
Call laboratory for additional acceptable specimen collection 
containers.
Minimum:
2 ml whole blood in light green top tube
Testing
Schedule:
24 hrs/day, 7 days a week, including holidays.
Analytic Time:
2 hours (upon receipt in laboratory)
Reference Range:
Normal:  243 - 894 pg/ml
Indeterminant:  175-242 pg/ml
Deficient:  is less than 175 pg/ml
Comments:
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 1000.
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
Sample
Processing:
Centrifuge at 3000 RPM for 10 minutes.
Aliquot plasma into labeled container and cap.
Sample
Storage:
Refrigerate up to 24 hours.
Protect specimen from light.
Transport
Instructions:
Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.
CPT Code:
82607

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Updated: 01/23/2008