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Technical Literature

1.Intended use
The H. pylori IgA test is a rapid ELISA method for the detection of IgA class antibodies to cellular components of Helicobacter pylori. It is intended as an aid to diagnosis of H. pylori  infections.  The components of the test are for in vitro diagnostic use only.

2. Explanation of the Test
H.pylori infection is a major causative factor in gastritis, gastric and duodenal ulcers and gastric cancer. The organism can be demonstrated by culture or by histological staining in 90% of affected patients. The distribution of the organism within the gut lining is patchy and can be missed during endoscopy.
Detection of serum antibodies to H.pylori is a reliable indicator of H.pylori infection and provides a rapid, simple and non-invasive method for diagnosing H.pylori infection. 
The kit uses an antigen preparation that has been partially purified to yield principally high molecular weight H.pylori membrane proteins.

3. Principle of the test
Diluted serum samples are incubated with partially purified H.pylori antigens immobilised on microtitre wells.  After washing away unbound serum components, rabbit anti-human IgA conjugated to horseradish peroxidase is added to the wells and this binds to surface-bound antibodies in the second incubation. Unbound conjugate is removed by washing, and a solution containing 3,3’,5,5’-tetramethylbenzidine (TMB) and enzyme substrate is added to trace specific antibody binding. Addition of stop solution terminates the reaction and provides the appropriate pH for colour development.  The optical densities of the standards, controls and samples are measured using a microplate reader at 450nm.  Optical density is directly proportional to antibody activity in the sample. 

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