Anti-Intrinsic Factor

Specialist

also —

What it isAutoantibodies that block intrinsic factor — the stomach-made protein required for B12 absorption in the ileum.

DoesCauses pernicious anemia by preventing B12 absorption regardless of dietary intake.

GoodNegative result rules out classical pernicious anemia.

BadPositive anti-intrinsic factor confirms pernicious anemia and indicates lifelong B12 supplementation or injections are needed.

Standard

Negative.

Optimal

Negative (lower is good)

Modifiers

Persists indefinitely.

How to optimize

Lifestyle: —
Diet: Cannot meet B12 needs orally if absorption blocked.
Supplements: High-dose oral B12 (1000–2000µg/day) or sublingual; some require injections.
Peptides: —
Drugs: B12 (cyanocobalamin or hydroxocobalamin) injections.

within Autoimmune