Intrinsic Factor Ab ELISA

Intrinsic factor is a solid phase enzyme immunoassay with recombinant human intrinsic factor for the quantitative detection of IgG antibodies against intrinsic factor. The assay is a tool in the diagnosis of pernicious anaemia (Biermer`s anaemia) Pernicious anaemia is the end stage of an autoimmune gastritis (type A gastritis) resulting in destruction of the gastric mucosa. A small proportion (10-15%) of patients with autoimmune gastritis develop pernicious anaemia. Pernicious anaemia is the most common cause of vitamin B12 deficiency in Western populations. It is caused by a lack of intrinsic factor, a glycoprotein needed to absorb vitamin B12 from the gastrointestinal tract. Intrinsic factor is produced by gastric parietal cells. Vitamin B12, in turn, is necessary for the formation of red blood cells. Pernicious anaemia usually does not appear before the age of 30. The average age at diagnosis is 60 years. In fact, one recent study revealed that nearly 2 percent of individuals over 60 years old suffer from pernicious anaemia. Furthermore, slightly more women than men are affected. The disease can affect all ethnic groups, but occurs more often among people of Scandinavian or Northern European descent. Autoantibodies in pernicious anaemia target parietal cells and intrinsic factor. Antibodies against parietal cells are 80-90% sensitive but can be detected also in up to 5% of the healthy population. Antibodies against intrinsic factor show a sensitivity of 50-70% with a specificity of 100% in a population of healthy blood donors.