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Intrinsic Factor Antibody


Blood
Test performed by: LabPLUS VIM Serology


Specimen Collection
SST3.5 mL SST Serum (Preferred)
Plain4 mL Plain Serum
Microsample500 uL Microsample Serum
Reference Intervals

Uncertainty of Measurement = 30%


Equivocal - Units: U/mL
Age RangeEither Sex
All10 - 24.9
Negative
Age RangeEither Sex
All< 9.9
High
Age RangeEither Sex
All>= 25

Turnaround Time: Between 1 week and 2 weeks
Diagnostic Use and Interpretation

Intrinsic Factor (IF) is an essential glycoprotein involved in the transport of vitamin B12 across the intestinal mucosa. This protein binds to the vitamin, forming a complex which only then allows the absorption of B12 into the bloodstream. Vitamin B12 is required for the maturation of erythrocytes and a deficiency leads to the development of anaemia.

Failure to either produce or utilise IF results in pernicious anaemia. Type I autoantibodies to IF block the formation of the IF-B12 complex, whereas type II autoantibodies bind to other sites on the complexes, preventing absorption.

Radioimmunoassay will only detect type I (blocking autoantibodies), and can produce false positive results in patients with high serum vitamin B12 levels.

The determination of anti-IF IgG by ELISA using recombinant human IF as the solid phase allows the differentiation between autoimmune pernicious anaemia, non-autoimmune pernicious anaemia (atrophic gastritis, pancreatic exocrine insufficiency) and other forms of vitamin B12 related anaemias.

  Reference

1. Generic Assays IFU

See also:

Parietal Cell Antibodies


Contact Information

For further information contact the laboratory, (09) 307 4949 ext 22103 or:
Associate Professor Rohan Ameratunga , Immunopathologist: Locator 93-5724,  

Dr Richard Steele , or  The LabPLUS Immunology Team



Last updated at 11:51:13 03/05/2022