What is this test?
Antibodies to intrinsic factor can interfere with vitamin B12 absorption and are associated with pernicious anemia.
Why might it be ordered?
- In vitamin B12 deficiency or macrocytic anemia without a clear nutritional cause.
- To differentiate pernicious anemia from other causes of low vitamin B12.
What sample is needed?
A healthcare professional collects a venous blood sample. Depending on the method, the laboratory uses serum or plasma.
How should you prepare?
Tell the laboratory about all medicines, hormone treatments, vitamins and supplements you take. Do not stop or change treatment unless your clinician tells you to. Follow any instructions about fasting and the time of collection.
How should you understand the result?
A positive result supports pernicious anemia when the other laboratory findings fit. A negative result does not rule it out completely. A positive result means the tested antibodies were detected, but it does not establish a diagnosis on its own. A negative result does not rule out every autoimmune condition.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.