Intrinsic Factor Antibody IFA Test

An Intrinsic Factor Antibody (IF Antibody) test is ordered to diagnose the cause of Vitamin B12 deficiency. Vitamin B12 deficiency points to pernicious anaemia. Vitamin B12 is required to produce a healthy amount of red blood cells (RBCs). Intrinsic factor is a glycoprotein secreted by the cells of the stomach lining and in small quantities by the salivary glands. It binds to Vitamin B12 for its assimilation into the bloodstream. Hence, a deficiency of intrinsic factor causes a reduction in Vit. B12 resulting in pernicious anaemia. The absence of the intrinsic factor may be caused by a thinning of the lining of the stomach or some kind of removal of the stomach lining through surgery. People who follow extremely strict vegetarian diets like Veganism are also susceptible. However, the liver can store Vit. B12 for upto 5 years. Hence, diet alone cannot lead to this condition.

This is basically a blood test and does not require any major preparation. You may fast for 12-14 hours before the test but this is not mandatory. This test is ordered when Vit B12 deficiency is suspected because of symptoms like paleness, fatigue, tingling and/or numbness in the feet and/or hands. However, a more suggestive symptom is the presence of abnormally large RBCs that may be observed in the course of a routine blood test like the CBC (Complete Blood Count).

Vitamin B12 is usually found in animal meat, dairy products, fish and eggs. It can also be found in yeast extracts. Dietary supplements can be taken to improve levels of Vit. B12. However, people whose bodies cannot absorb Vit. B12 need regular injections. Some children inherit the condition of lower levels of the intrinsic factor, causing symptoms of pernicious anaemia. Pernicious anaemia is observed more commonly in people who have other immune system related issues like hypothyroidism, Addison’s disease and Type 1 Diabetes. Patients with pernicious anaemia may exhibit neurological symptoms like clumsiness which may end up being permanent if it the condition is not treated in time.

On observing any of the symptoms related to pernicious anaemia, tests are ordered to determine the levels of Vit. B12, iron and folate in the blood. The level of methylmalonic acid is also tested as this increases in case of B12 deificiency. Once the above are done, tests are ordered to determine IF antibody levels. After this a confirmatory bone marrow test is done to rule out any other causes for the anaemia or abnormal RBCs. Once a deficiency in Vit. B12 is detected the treatment is primarily to replenish Vit B12 in the body.