Home
HelpOrder Code ACASM Pernicious Anemia Cascade, Serum
Reporting Name
Pernicious Anemia CascadeUseful For
Diagnosis of pernicious anemia
Diagnosis of vitamin B12 deficiency-associated neuropathy
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| IFBPA | Intrinsic Factor Blocking Ab, S | Yes, (order IFBA) | No |
| MMAPA | Methylmalonic Acid, QN, S | Yes, (order MMAS) | No |
| GASTR | Gastrin, S | Yes, (order GAST) | No |
Testing Algorithm
If the vitamin B12 concentration is less than 150 ng/L, then the intrinsic factor blocking antibody (IFBA) test is performed at an additional charge.
If IFBA result is negative or indeterminate, then the gastrin test is performed at an additional charge.
If the vitamin B12 concentration is 150 to 400 ng/L, then the methylmalonic acid (MMA) test is performed at an additional charge.
If the MMA result is greater than 0.40 nmol/mL, then the IFBA test is performed at an additional charge.
If the IFBA test is negative or indeterminate, then the gastrin test is performed at an additional charge.
For more information see Vitamin B12 Deficiency Evaluation.
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumOrdering Guidance
Ask patients if they have received a vitamin B12 injection or radiolabeled vitamin B12 injection within the last 2 weeks. Patient results will not reflect deficiency or malabsorption after recent B12 injection. If patient has received such an injection within the past 2 weeks, this test should not be ordered.
Specimen Required
Patient Preparation:
1. Patient should fast for 8 hours.
2. For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).
3. For 1 week before specimen collection, if medically feasible, patient should not take proton pump inhibitors (omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, and rabeprazole).
4. For at least 2 weeks before specimen collection, patient should not take or receive drugs that interfere with gastrointestinal motility (eg, opioids).
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 3 mL
Collection Instructions:
1. Centrifuge, divide specimen into 3 plastic vials:
Vial 1 (B12PA): 1 mL of serum
Vial 2 (PAMMA): 1.5 mL of serum
Vial 3 (PAGAS): 0.5 mL of serum
2. Band specimens together and send frozen.
Specimen Minimum Volume
1.6 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 30 days |
| Refrigerated | 24 hours |
Special Instructions
Reference Values
180-914 ng/L
Day(s) Performed
Monday through Saturday
CPT Code Information
82607
82941-(if appropriate)
83921-(if appropriate)
86340-(if appropriate)
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | Reject |
Method Description
The Access Vitamin B12 assay is a competitive-binding immunoenzymatic assay. The sample is added to a reaction vessel along with alkaline potassium cyanide and dithiothreitol. This treatment denatures vitamin B12 binding proteins and converts all forms of vitamin B12 to the cyanocobalamin form. After neutralization, intrinsic factor-alkaline phosphatase conjugate and paramagnetic particles coated with goat anti-mouse IgG:mouse monoclonal anti-intrinsic factor are added to the sample. Vitamin B12 in the sample binds to the intrinsic factor conjugate, preventing the conjugate from binding to the solid phase anti-intrinsic factor. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field, while unbound materials are washed away. A chemiluminescent substrate is added to the vessel, and the light generated by the reaction is measured with a luminometer. The photon production is inversely proportional to the concentration of vitamin B12 in the sample. The amount of analyte in the sample is determined by means of a stored, multipoint calibration curve.(Package insert: ACCESS Vitamin B12. Beckman Coulter, Inc; 10/2023)
Method Name
Immunoenzymatic Assay
Forms
If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.