Intrinsic Factor Antibody

Share this page:
Looking for your tests results? Looking for reference ranges?
Also known as: IF Antibody; IF Antibody Type I or Type II; Intrinsic Factor Binding Antibody; Intrinsic Factor Blocking Antibody; Anti-intrinsic Factor
Formal name: Intrinsic Factor Antibody

At a Glance

Why Get Tested?

To help diagnose pernicious anemia

When to Get Tested?

As part of an investigation, when you have anemia and/or neuropathy that may be due to a vitamin B12 deficiency; when you have red blood cells that are much larger than normal (macrocytic)

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

You should wait at least 48 hours after receiving a vitamin B12 injection to have a blood sample taken. The doctor may prefer not to draw a blood sample for the test within 2 weeks of an injection.

The Test Sample

What is being tested?

This test detects intrinsic factor antibody in the blood. Intrinsic factor (IF) is a protein produced by a type of specialized cells that line the stomach wall known as parietal cells that is required for the absorption of vitamin B12 from the diet. During digestion, stomach acids release vitamin B12 from food and intrinsic factor binds to the vitamin B12 and allows it to be absorbed at a specific segment of the small intestine. Among other functions, vitamin B12 is important in the production of red blood cells. Without sufficient intrinsic factor, vitamin B12 goes largely unabsorbed and the body cannot produce enough normal red blood cells, leading to anemia. Besides anemia, decrease in the numbers of neutrophils and platelets (neutropenia, thrombocytopenia) may also occur.

Anemia that is due to a lack of intrinsic factor is called pernicious anemia. This condition occurs primarily when the body’s immune system targets its own tissues and develops antibodies directed against the parietal cells and/or the intrinsic factor. These antibodies can damage the parietal cells and disrupt intrinsic factor production or prevent intrinsic factor from carrying out its function.

There are two types of intrinsic factor antibodies: intrinsic factor blocking antibody, which blocks the binding of vitamin B12 to intrinsic factor, and intrinsic factor binding antibody, which binds to the vitamin B12-instrinsic factor complex. The intrinsic factor blocking antibody is more specific for pernicious anemia and is the one that is usually tested.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

If you receive a vitamin B12 injection, you should wait 48 hours before having your blood drawn for this test. The doctor may prefer not to draw a blood sample for the test within 2 weeks of an injection.

The Test

Common Questions

Ask a Laboratory Scientist

This form enables you to ask specific questions about your tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. If your questions are not related to your lab tests, please submit them via our Contact Us form. Thank you.

* indicates a required field



Please indicate whether you are a   
  
  



You must provide a valid email address in order to receive a response.



| Read The Disclaimer


Spam Prevention Equation

| |

Article Sources

« Return to Related Pages

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 592-593.

(Revised 2011 April). Pernicious Anemia. National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/prnanmia/prnanmia_what.html through http://www.nhlbi.nih.gov. Accessed August 2011.

Chen, Y. (Updated 2010 January 31). Lack of Intrinsic Factor. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/001155.htm. Accessed August 2011.

Vorvick, L. (Updated 2010 January 31). Intrinsic factor. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/002381.htm. Accessed August 2011.

Frank, E. et. al. (Updated 2010 September). Megaloblastic Anemia. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/MegaloblasticAnemia.html through http://www.arupconsult.com. Accessed July 2011.

(© 1995–2011). Unit Code 9335: Intrinsic Factor Blocking Antibody, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/9335 through http://www.mayomedicallaboratories.com. Accessed July 2011.

Mayo Clinic Staff (2011 March 4). Vitamin Deficiency Anemia. MayoClinic.com [On-line information]. Available online at http://www.mayoclinic.com/health/vitamin-deficiency-anemia/DS00325/METHOD=print through http://www.mayoclinic.com. Accessed July 2011.

(Reviewed 2011 June 24). Dietary Supplement Fact Sheet: Vitamin B12. NIH Office of Dietary Supplements [On-line information]. Available online at http://ods.od.nih.gov/factsheets/VitaminB12-QuickFacts/ through http://ods.od.nih.gov. Accessed August 2011.

(Reviewed 2011 April 4). Vitamin B12. MedlinePlus Drug Information [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/druginfo/natural/926.html through http://www.nlm.nih.gov. Accessed August 2011.

Schick, P. (Updated 2011 May 26). Megaloblastic Anemia. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/204066-overview through http://emedicine.medscape.com. Accessed August 2011.

Conrad, M. (Updated 2011 May 26). Pernicious Anemia. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/204930-overview through http://emedicine.medscape.com. Accessed August 2011.

Dugdale, D. (Updated 2008 November 23). Pernicious anemia. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000569.htm. Accessed August 2011.

Chen, Y. (Updated 2010 January 31). Anemia – B12 deficiency. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000574.htm. Accessed August 2011.

OH, R. and Brown, D. (2003 March 1). Vitamin B12 Deficiency. Am Fam Physician. 2003 Mar 1;67(5):979-986. [On-line information]. Available online at http://www.aafp.org/afp/2003/0301/p979.html through http://www.aafp.org. Accessed August 2011.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 632-633.

Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson R, Pincus M, eds. Philadelphia, PA: Saunders Elsevier: 2007 Pp 508-509.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER, Bruns DE, eds. St. Louis: Elsevier Saunders; 2006, Pp 1103.