Test Catalog

Test ID: ACASM    
Pernicious Anemia Cascade, Serum

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

If the vitamin B12 concentration is less than 150 ng/L, then the intrinsic factor blocking antibody (IFBA) test is performed. If IFBA result is negative or indeterminate, then the gastrin test is performed.

If the vitamin B12 concentration is 150 to 400 ng/L, then the methylmalonic acid (MMA) test is performed. If the MMA result is greater than 0.40 nmol/mL, then the IFBA test is performed.


See Vitamin B12 Deficiency Evaluation in Special Instructions.

Specimen Type Describes the specimen type validated for testing


Specimen Required Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Patient Preparation:

1. This test should not be ordered on patients who have received a vitamin B12 injection within the last 2 weeks.

2. Patient should be fasting for 8 hours.

3. If medically feasible, proton pump inhibitor (omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, and rabeprazole) therapy should be discontinued 1 week before measurement of serum gastrin levels.

4. Drugs that interfere with gastrointestinal motility (eg, opioids) should be discontinued for at least 2 weeks before serum gastrin testing.


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 4 mL

Collection Instructions:

1. Divide specimen into 3 plastic vials, 1 containing 1 mL (label as PAGAS), 1 containing 1.5 mL (label as PAMMA), and 1 containing 1.5 mL (label as B12PA).

2. Band specimens together.

Special Instructions Library of PDFs including pertinent information and forms related to the test


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

Specimen Minimum Volume Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

2.3 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK
Gross icterus Reject

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen TypeTemperatureTimeSpecial Container
SerumFrozen (preferred)30 days
 Refrigerated 24 hours