Specimen

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

2 ml whole blood in light green top tube

Delivery Instructions:

Deliver to laboratory immediately after collection.

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:

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

CPT Code:

82607

See Additional Information:
Specimens Requiring Immediate Delivery