• Also Known As:
  • Gastric Parietal Cell Antibody
  • Anti-parietal Cell Antibody
  • Anti-GPA
  • AGPA
  • APCA
  • Formal Name:
  • Gastric Parietal Cell Antibody
  • IgG
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At a Glance

Why Get Tested?

To help diagnose pernicious anemia, the most common cause of vitamin B12 deficiency

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 may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Lab Tests Online. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.

Lab Tests Online is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.

The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.

If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.

Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.

While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”

For more information, please read the article Reference Ranges and What They Mean.

What is being tested?

Parietal cell antibodies are autoantibodies, proteins produced by the immune system that mistakenly target a type of specialized cells that line the stomach wall. This test detects these antibodies in the blood to help diagnose pernicious anemia.

Pernicious anemia is an autoimmune condition that can occur when the body’s immune system targets its own tissues and develops antibodies directed against the parietal cells and/or intrinsic factor.

  • Parietal cells are specialized cells in the stomach that make acid to help in food digestion and also make intrinsic factor.
  • Intrinsic factor is required for the absorption of vitamin B12 from food.

During digestion, stomach acids produced by parietal cells release vitamin B12 from food, which binds to intrinsic factor to form a complex. The formation of this complex allows vitamin B12 to be absorbed in the small intestine. Among having functional roles in the brain and nervous system, vitamin B12 is important in the production of red blood cells (RBCs).

When the body’s immune system mistakenly targets its own tissues and develops antibodies directed against parietal cells and/or intrinsic factor, it can cause inflammation and progressively damage the parietal cells. This autoimmune condition, called autoimmune atrophic gastritis, can disrupt the production or function of intrinsic factor.

Without sufficient intrinsic factor, vitamin B12 goes largely unabsorbed, leading to vitamin B12 deficiency. Deficiency in vitamin B12 can result in megaloblastic anemia, characterized by the production of fewer but larger red blood cells (macrocytes). Vitamin B12 deficiency can also result in nerve-related signs and symptoms (neuropathy), such as numbness and tingling that start first in the hands and feet, muscle weakness, slow reflexes, loss of balance and unsteady walking. Other disorders can cause vitamin B12 deficiency and result in megaloblastic anemia. When it is due to a lack of intrinsic factor, it is called pernicious anemia. Besides anemia, a decrease in the numbers of neutrophils and platelets (neutropenia, thrombocytopenia) may also occur.

The tests for parietal cell and/or intrinsic factor antibodies may be used along with several other tests, such as complete blood count (CBC) and blood smear, to help diagnose pernicious anemia.

Common Questions

How is it used?

A parietal cell antibody test may be used along with or following an intrinsic factor antibody test to help determine the cause of a vitamin B12 deficiency and to help confirm a diagnosis of pernicious anemia.

It is usually used as a follow-up test after other laboratory tests, such as a vitamin B12 test, a methylmalonic acid test, or a complete blood count (CBC) with a blood smear examination, establish that a person has a vitamin B12 deficiency and associated megaloblastic anemia and/or neuropathy.

When is it ordered?

The parietal cell antibody test is not a frequently ordered test because it is not as specific as the intrinsic factor antibody test. It may be ordered when a person has signs and symptoms that suggest a vitamin B12 deficiency and when pernicious anemia is suspected. Signs and symptoms may include:

  • Larger than normal red blood cells (RBCs); these are often detected before the other signs and symptoms emerge, found, for example, with a CBC during routine testing for a health examination.
  • Pale complexion
  • Weakness, fatigue
  • Numbness and tingling in the feet and/or hands that may be due to neuropathy

These findings usually prompt vitamin B12 and folate testing and may lead to methylmalonic acid testing (an early indicator of vitamin B12 deficiency) and homocysteine testing.

An intrinsic factor antibody test and parietal cell antibody test may be ordered as follow-up tests when a person has a decreased vitamin B12 level and increased methylmalonic acid and homocysteine levels.

What does the test result mean?

The results of this test are often taken into consideration with the results of other laboratory tests to help make a diagnosis.

A decreased vitamin B12 level and/or increased methylmalonic acid and homocysteine levels as well as a positive test result for intrinsic factor antibodies and/or parietal cell antibodies means that it is likely that the person tested has pernicious anemia.

A negative test result does not necessarily mean that a person does not have pernicious anemia. At least 10% of those affected will not have parietal cell antibodies.

Parietal cell antibodies are not as specific as intrinsic factor antibodies. About 90% of those with pernicious anemia will have parietal cell antibodies, but they may also be found in:

  • Up to 50% of people with gastritis (inflammation of the stomach lining)
  • Up to 30% of people with inflammation of the thyroid gland (thyroiditis)
  • A variety of other conditions and autoimmune disorders
  • A small percentage of the general population

The parietal cell antibody test is not used to diagnose or monitor these conditions.

Is there anything else I should know?

Vitamin B12-associated anemia may take several years to develop as a normal person typically has large stores of B12 in reserve. Symptoms tend to emerge only when these stores become depleted.

Recent evidence indicates that people with type 1 diabetes may have an increase in the risk of developing parietal cell antibodies.

Can I prevent, decrease, or get rid of parietal cell antibodies?

No, they are produced by your immune system and do not respond to preventive measures or lifestyle changes. The associated vitamin B12 deficiency, however, can usually be successfully treated and managed.

If I can't absorb vitamin B12, how can I get enough?

Periodic B12 injections can be given. If you are able to absorb some B12, then high doses of oral supplementation may help. You should consult with your healthcare practitioner for specific, appropriate treatment options.

Should everyone have a parietal cell antibody test?

No. It is not intended as a general screening test. It is usually only performed when a person has a demonstrated vitamin B12 deficiency to help determine the cause.

How long will it take for results?

It depends on the laboratory performing the test. This test requires specialized equipment and is not offered by every laboratory. In some cases, your blood sample will need to be sent to a reference laboratory and it may take a few days before results are available.

View Sources

Sources Used in Current Review

2017 review performed by Bereneice Madison, PhD, MT(ASCP) and the Editorial Review Board.

Pan XF, Gu J, and ZY Shan. 2015. Type 1 Diabetic Populations Have an Increased Prevalence of Parietal Cell Antibody. A Systematic Review and Meta-Analysis. Medicine 94: 38, 2015.

Toh Ban-Hock 2016. Pathophysiology and laboratory diagnosis of pernicious anemia. Immunol Res DOI 10.1007/s12026-016-8841-7.

Bizzaro N and A Antico 2014. Diagnosis and classification of pernicious anemia. Autoimmunity Reviews 13: 565–568.

(July 6, 2016) Zayouna N. Atrophic Gastritis. Medscape. Available online at http://emedicine.medscape.com/article/176036-overview#a5. Accessed May 2017.

(Updated: 11/28/2016) Genetic and Rare Diseases Information Center. Autoimmune atrophic gastritis. Available online at https://rarediseases.info.nih.gov/diseases/10310/autoimmune-atrophic-gastritis. Accessed May 2017.

Sources Used in Previous Reviews

Eisner, T. (Updated 2012 February 5). Antiparietal cells antibodies test. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003351.htm. Accessed July 2013.

(© 1995–2013). Parietal Cell Antibodies, IgG, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/83728. Accessed July 2013.

Frank, E. (Updated 2013 July). Megaloblastic Anemia. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/MegaloblasticAnemia.html?client_ID=LTD. Accessed July 2013.

Schick, P. (Updated 2012 February 24). Megaloblastic Anemia. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/204066-overview. Accessed July 2013.

Cohen, S. (Updated 2012 February). Gastritis. Merck for Healthcare Professionals [On-line information]. Available online through http://www.merckmanuals.com. Accessed July 2013.

What Is Pernicious Anemia? National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/health-topics/topics/prnanmia/. Accessed July 2013.

Schick, P. and Conrad, M. (Updated 2013 February 27). Pernicious Anemia. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/204930-overview. Accessed July 2013.

Gersten, T. (Updated 2012 February 8). Pernicious anemia. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000569.htm. Accessed July 2013.

(© 1995–2013). Intrinsic Factor Blocking Antibody, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/9335. Accessed July 2013.

Andres, E. and Serraj, K. (2012 September 10). Optimal management of pernicious anemia. J Blood Med. v3: 97–103. [On-line information]. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3441227/. Accessed July 2013.

Sepulveda, A. and Mukherjee, S. (Updated 2012 September 27). Atrophic Gastritis. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/176036-overview#showall. Accessed July 2013.

Mukherjee, S. and Sepulveda, A. (Updated 2012 March 29). Chronic Gastritis. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/176156-overview. Accessed July 2013.

Lahner, E. and Annibale, B. (2009 November 7). Pernicious anemia: New insights from a gastroenterological point of view. World J Gastroenterol v15 (41): 5121–5128. [On-line information]. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2773890/. Accessed July 2013.

Mayo Clinic Staff (2011 March 4). Vitamin deficiency anemia. Mayo Clinic [On-line information]. Available online at http://www.mayoclinic.com/health/vitamin-deficiency-anemia/DS00325. Accessed July 2013.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 826-827.

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