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Intrinsic Factor Antibody (IFA)
minimum sample volume required ~ 5ml
Test Code: IFA
Tube type: SST
Other acceptable tube types
Lithium heparin (pale green)
Special instructions
Do not request in patients with
1. Previous POSITIVE result
2. B12 injection within the past week
3. History of gastrectomy or terminal ileum resection
Time limit for add on
2 days
Interfering substances
None known
Minimum retesting interval
Test should not be repeated within 56 days
Reference range
Results reported as negative, positive or equivocal, no numerical value provided
Units
NA
Linked to
B12, GPC
Turnaround Time
1
day
Department: Biochemistry
Clinical Application
From 17/09/24 intrinsic factor antibody assay performed on Beckman Access analyser. Assay detects Type I (blocking) intrinsic factor antibodies.
The presence of Intrinsic factor antibodies can be used in conjunction with other laboratory tests and clinical findings to aid in the diagnosis of pernicious anaemia. Intrinsic factor antibody testing should be considered in patients with vitamin B12 <145 ng/L or in patients where vitamin B12 is persistently (>6 months) <180 ng/L (see vitamin B12 guidance)
Type 1 intrinsic factor antibodies prevent vitamin B12 uptake. They are present in up to 76% of patients with pernicious anaemia; a negative or equivocal result does not exclude pernicious anaemia entirely. If intrinsic factor antibodies are negative and B12 deficiency fails to respond to oral B12 supplementation, vitamin B12 injection should be considered as an alternative.
Webpage updated: September 2024
