Intrinsic Factor Antibody (IFA)

Immunology

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Description

Antibodies against intrinsic factor (IFA) are seen in 50-70% of patients with pernicious anaemia (PA) [1]. Gastric parietal cell antibodies are considered an appropriated screening test for pernicious anaemia and intrinsic factor antibodies are ideally used to confirm if a GPC has been masked by another antibody (for example anti-mitochondrial antibodies) [1]. There are two types of intrinsic factor antibody that can be detected; type I that block the binding of B12 to intrinsic factor and type II that block the uptake of the intrinsic factor-B12 complex. PA is caused by chronic atrophic gastritis and subsequent reduced absorption of vitamin B12 in the ileum. This results in megaloblastic anaemia and often neurological disorders.

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Indications

Pernicious anaemia and antral gastritis.

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Sample Type

2mL Serum (Gel 5mL Yellow tube) or 2mL plasma (EDTA, heparin or citrate). Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

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Reference Range

Negative = Normal

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Turnaround Time

Within 5 days

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Testing Frequency

Weekly

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References

Khan S, et al. Limited value of testing for intrinsic fcator antibodies with negative gastric parietal cell antibodies in pernicious anaemia. J Clin Pathol. 2009. 62: 439-441. [Ref 1]Toh BH, Aderuccio F. Pernicious anaemia. Autoimmunity. 2004. 37(4):357-361.Cummins D, Ardeman S. Intrinsic factor antibodies and pernicious anaemia. Lancet. 1991. 338:383-384.

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See Also

Gastric parietal cell antibody (FATS) and vitamin B12 quantitation.

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