Intrinsic Factor (IF) IgG Antibody Test
Intrinsic Factor (IF) IgG Antibody Test
Intrinsic Factor (IF) IgG Antibody testing is a diagnostic assay to determine the root cause of vitamin B-12 deficiency, which leads to pernicious anemia. Vitamin B12 (cobalamine) plays an essential role in red blood cell formation, nerve function and the production of DNA inside the cells to keep the body healthy. However, your body does not make enough vitamin B-12; rather, acquire it from a balanced diet to produce healthy red blood cells from the bone marrow.
What is the Intrinsic Factor IgG Antibody Used For?
Your doctor might request intrinsic factor IgG antibody testing
To diagnose pernicious anemia in individuals who suffer from frequent infections
As part of evaluation for anemia or neuropathy in individuals experiencing numbness or tingling in the extremities
When a person’s peripheral blood smear shows larger than normal red blood cells(macrocytic)
Symptoms of Pernicious anemia or Vitamin B 12 deficiency
Most individuals with pernicious anemia may experience
Weakness or tiredness
Pale skin
Constipation and loss of appetite
Diarrhea
Weak muscles
Numbness and tingling in hands and feet
Rapid heartbeat
Shortness of breath
Loss of balance
Smooth and tender tongue
Preparation for Test
You may need to fast for 8-10 hours before the blood is drawn for the intrinsic factor IgG antibody test. Also, tell your doctor about all your medications since they can affect the test results. However, do not stop any medicine without a doctor’s consultation.
Interpretation of Test Results
To make a proper diagnosis, the results of the intrinsic factor antibody (IF antibody) test are often considered along with the results of other laboratory tests and interpreted as follows:
|
Levels of Intrinsic factors (AU/ml) |
Interpretation |
|
Less than 1.20 |
Negative for IF antibodies, but doesn't rule out pernicious anemia |
|
1.20 - 1.53 |
Normal |
|
Greater than 1.53 |
Positive for IF antibodies, may be due to vitamin B 12 deficiency or other autoimmune disorders like Grave’s disease, type 1 diabetes etc. Additional testing is recommended for a definitive diagnosis |
*AU/ml - antibody unit per milliliter
FAQs
When is the Intrinsic Factor (IF) IgG Antibody test ordered?
The Intrinsic Factor IgG Antibody is not a routine test but may be ordered when a person is suspected of pernicious anemia. The results will be further confirmed by methylmalonic acid testing, an early indicator of vitamin B12 deficiency.
Can medication affect my results of the IF antibody test?
Yes, certain drugs and supplements, such as colchicine, metformin (a diabetic drug), antacids, vitamin C, and B12, can impact the results of IF antibody testing.
Can I get rid of intrinsic factor antibodies?
No, you can’t get rid of IF antibodies because they are produced by your immune system and do not respond to lifestyle changes. However, they can be successfully treated and managed by supplementation of the right dose of vitamin B12.
What are the causes of vitamin B12 deficiency?
The most common causes of vitamin B12 deficiency include:
- Lack of vitamin B12 in the diet
- Malabsorption disorders (for example, celiac disease)
- Lack of intrinsic factors due to abnormal antibodies
- Pregnancy
- Decreased stomach acidity (seen in older adults)
- Surgical removal of the small intestine where vitamin B12 is absorbed
Does this test pose any risks?
The Intrinsic factor IgG test, being a blood test, has minimal risks. These include bleeding, infection, bruising, and feeling lightheaded. You might even feel a slight sting, pain, or mild soreness at the needle prick site.
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