Intrinsic Factor Anti- Body, Serum

Intrinsic Factor Antibody, Serum

What it is

The Intrinsic Factor Antibody, Serum test detects antibodies that attack intrinsic factor, a protein made in the stomach that helps absorb vitamin B12. The presence of these antibodies interferes with vitamin B12 absorption and is strongly associated with pernicious anemia, an autoimmune disorder that leads to vitamin B12 deficiency and related complications.

Uses

This test is primarily used to diagnose pernicious anemia in patients with unexplained vitamin B12 deficiency. It helps distinguish pernicious anemia from other causes of low B12 such as dietary deficiency or malabsorption. It may also be ordered as part of a broader evaluation of unexplained anemia, neurological symptoms, or gastrointestinal issues.

Symptoms That May Lead to the Test

Doctors may recommend this test if you show signs of vitamin B12 deficiency, including fatigue, weakness, pale or jaundiced skin, numbness or tingling in hands and feet, balance problems, memory loss, mood changes, or unexplained anemia. It is especially important in patients suspected of having autoimmune-related conditions.

Abnormal Results

Positive for Intrinsic Factor Antibodies: Strongly supports the diagnosis of pernicious anemia and indicates impaired vitamin B12 absorption. This often requires long-term vitamin B12 supplementation.

Negative Result: Suggests the absence of intrinsic factor antibodies. However, pernicious anemia can still be present, so additional tests (such as parietal cell antibody or methylmalonic acid) may be necessary.

Risks

The test involves a routine blood draw, with minimal risks such as mild pain, bruising, or dizziness at the puncture site. Serious complications are extremely rare.