What are other Names for this Test? (Equivalent Terms)
- Gastric Intrinsic Factor Blood Test
- IFAB Blood Test
- Intrinsic Factor Blocking Antibody Blood Test
What is Intrinsic Factor Antibody Blood Test? (Background Information)
- Intrinsic factor (IF) is a protein produced by the parietal cells located in the stomach. It is necessary for the absorption of vitamin B12 in the small intestine
- Vitamin B12, also called cobalamin, is essential for red blood cell production, nervous system health, and tissue maintenance and repair. It is made by bacteria in the intestines
- Intrinsic factor antibodies are defense proteins made by the immune system that mistakenly target vitamin B12, the parietal cells that make IF, and/or the binding site of IF to the small intestine instead of foreign invaders
- Intrinsic factor antibodies interfere with vitamin B12 absorption, causing a reduction in vitamin B12 stores and eventually a vitamin B12 deficiency. Because vitamin B12 is necessary for the production of red blood cells, vitamin B12 deficiency may lead to a specific type of anemia called pernicious anemia
- The Intrinsic Factor Antibody Blood Test detects antibodies that target the intrinsic factor. It helps diagnose pernicious anemia
What are the Clinical Indications for performing the Intrinsic Factor Antibody Blood Test?
Following are the clinical indications for performing the Intrinsic Factor Antibody Blood Test:
- Following up to a finding of vitamin B12 deficiency
- Pale appearance
- Trouble breathing
- Lightheadedness and dizziness
- Weight loss
How is the Specimen Collected for Intrinsic Factor Antibody Blood Test?
Following is the specimen collection process for Intrinsic Factor Antibody Blood Test:
Sample required: Blood
Process of obtaining a blood sample in adults:
- A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
- The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is penetrated using the needle
- The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed on the collection site, and the needle is removed
- The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
- The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Intrinsic Factor Antibody Blood Test Result?
- Detection of intrinsic factor antibodies signals a positive value for the Intrinsic Factor Antibody Blood Test. This may point to a diagnosis of pernicious anemia, in 50% of the cases
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- Certain factors interfere with the results of the Intrinsic Factor Antibody Blood Test. These include the presence of other autoimmune disorders and supplementation with cyanocobalamin
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.
What are some Useful Resources for Additional Information?
The following DoveMed website link is a useful resource for additional information:
Please visit our Laboratory Procedures Center for more physician-approved health information:
References and Information Sources used for the Article:
Daniels, R. (2010). Delmar's manual of laboratory and diagnostic tests: Organized by type of test (2nd ed.). Clifton Park, NY: Delmar Cengage Learning.
Kee, J. L. (2010). Laboratory and diagnostic tests with nursing implications (8th ed.). Upper Saddle River, NJ: Pearson.
Kumar, V., Abbas, A. K., Aster, J. C., & Robbins, S. L. (2013). Robbins basic pathology (9th ed.). Philadelphia, PA: Elsevier/Saunders.
Lichtin, A. E. (2016). Autoimmune hemolytic anemia. Retrieved from https://www.merckmanuals.com/home
Helpful Peer-Reviewed Medical Articles:
Pagana, K. D. (2013). Mosby's manual of diagnostic and laboratory tests. Elsevier Health Sciences.
Bain, B. J. (2014). Blood cells: a practical guide. John Wiley & Sons.
Bizzaro, N., & Antico, A. (2014). Diagnosis and classification of pernicious anemia. Autoimmunity reviews, 13(4), 565-568.
Stabler, S. P. (2013). Vitamin B12 deficiency. New England Journal of Medicine, 368(2), 149-160.
Shoenfeld, Y., Meroni, P. L., & Gershwin, M. E. (Eds.). (2013). Autoantibodies. Newnes.
Oslakovic, C., Cedervall, T., Linse, S., & Dahlbäck, B. (2012). Polystyrene nanoparticles affecting blood coagulation. Nanomedicine: Nanotechnology, Biology and Medicine, 8(6), 981-986.
Durandy, A., Kracker, S., & Fischer, A. (2013). Primary antibody deficiencies. Nature Reviews Immunology, 13(7), 519-533.
Yang, D. T., & Cook, R. J. (2012). Spurious elevations of vitamin B12 with pernicious anemia. New England Journal of Medicine, 366(18), 1742-1743.