Test Code ACASM Pernicious Anemia Cascade, Serum

Reporting Name

Pernicious Anemia Cascade

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Diagnosis of pernicious anemia

Diagnosis of vitamin B12 deficiency-associated neuropathy

Method Name

Immunoenzymatic Assay

Ordering 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:Â 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 Type

Serum

Specimen Minimum Volume

1.6 mL

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Serum	Frozen (preferred)	30 days
	Refrigerated	24 hours

Reject Due To

Gross hemolysis	Reject
Gross lipemia	OK
Gross icterus	Reject

Reference Values

180-914 ng/L

Interpretation

Vitamin B12 >400 ng/L	Results do not suggest B12 deficiency-no further testing.
Vitamin B12 150 to 400 ng/L	Borderline vitamin B12 level-methylmalonic acid (MMA) is performed. If MMA is >0.40 nmol/mL, then intrinsic factor blocking antibody (IFBA) is performed.
Vitamin B12 <150 ng/L	Vitamin B12 deficiency-IFBA is performed. If IFBA is negative or indeterminate, then gastrin is performed.
MMA ≤0.40 nmol/mL	This value implies that there is no vitamin B12 deficiency at the cellular level.
IFBA positive	Consistent with pernicious anemia, Graves disease, or Hashimoto thyroiditis.
Gastrin >200 pg/mL	Result consistent with pernicious anemia.
Gastrin <200 pg/mL	Result does not suggest pernicious anemia.

For more information see Vitamin B12 Deficiency Evaluation.

Day(s) Performed

Monday through Saturday

Report Available

Same day/1 to 4 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82607

82941-(if appropriate)

83921-(if appropriate)

86340-(if appropriate)

LOINC Code Information

Test ID	Test Order Name	Order LOINC Value
ACASM	Pernicious Anemia Cascade	2132-9

Result ID	Test Result Name	Result LOINC Value
B12PA	Vitamin B12 Assay, S	2132-9

Forms

If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.

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.