Test Overview
Test Methodology

Radiobinding Assay

Test Usage

Evaluation of conditions affecting vitamin B12 by altering the normal amounts of vitamin B12 binding protein, e.g., pregnancy.

Reference Range *

650 - 1340 pg/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

This test should not be ordered on patients who have recently received radioisotopes, therapeutically or diagnostically.

Test Details
Days Set Up
Varies; test performed twice per week
Analytic Time

2 days

Soft Order Code
MiChart Code
Misc Quest Diagnostics-Nichols (Sendout)
  • Transcobalamin Vit B12 Carrier Protein
  • Transcobalamin Vit B12 Carrier Protein
  • UBBC
  • B12 Combining Capacity
  • B12 Combining Capacity
Reference Laboratory
Mayo Wild 51 (ZW51) (Quest 928X)
Special Testing
Specimen Requirements
Collection Instructions

Collect blood in a red top tube from a fasting patient. Centrifuge, aliquot serum into plastic vial and freeze. Recently administered radioisotopes will interfere with this assay.

Special Handling

Fasting specimen.

Alternate Specimen
SST acceptable (Red top tube preferred). [11/07]
Normal Volume
1 ml serum
Minimum Volume
0.2 ml serum
Additional Information

Test sent to Mayo Medical Laboratories; performed by Quest Diagnostics.

CPT Code