H Pylori Rapid Test

H Pylori Rapid Test

The H pylori Stool Card is an immunochromatographic screening assay for the qualitative detection of Helicobacter pylori antigen in stool samples. In contrast to serum assays that are based on the detection of antibodies and remain positive for a relatively long time even if the infection has subsided, the H. pylori Stool Card indicates an active infection via the detection of antigen. Thus the test can be used for the determination of a suspected infection or re-infection with H. pylori or to monitor the success of an eradication therapy.

INTRODUCTION

Helicobacter pylori (also formerly known as Campylobacter pylori) is a spiral-shaped, Gram-negative bacterium with typical fl agella. It is capable of infecting the gastric mucosa. It causes several gastro-enteric diseases such as non-ulcerous dyspepsia, gastric and duodenal ulcer, active gastritis and might even increase the risk of stomach adeno carcinoma, so that it has been classified as carcinogenic agent type I.Various H. pylori strains have been isolated that differ in their virulence. Strains exhibiting a high virulence are generally characterized by the possession of the vacuolating cytotoxin (Vac A) and the so called cytotoxin associated genes cag pathogenicity island. These factors seem to be necessary for an effective infi ltration of the gastric mucosa and seem to be associated with the persistence of the infection. They also contribute to sudden infl ammatory responses, ulceration (gastric and duodenal ulcer), allergic episodes, and decrease of therapy efficacy. Especially the Cag A protein that is strongly immunogenic and is secreted into the gastric cells by a special mechanism is of special clinical importance. It has been widely reported in many literature articles that infected patients showing antibodies against the CagA gene product have a five times increased risk of developing gastric cancer if compared to a reference group infected with a CagA negative bacterial strain. At present several invasive and non-invasive approaches are available to detect the infection state.Invasive methodologies require endoscopy of the gastric mucosa with a histological, cultural and urease investigation. These examinations are expensive and time-consuming. Alternatively, non-invasive methods are available such as Breath Tests with isotope labelled urea, which are complicated and cost-intensive, or classical ELISA or immunoblotting assays. The H. pylori assay is an immunological rapid assay that takes advantage of a highly specifi c antibody/antigen reaction to detect bacterial protein of H. pylori (antigen) in stool samples.

PRINCIPLE OF THE TEST

The H. pylori Card is a non-invasive, qualitative, lateral flow immunoassay for the detection of H. pylori in human feces specimen. It is
precise, easy to perform, and rapid, generating the test result within several minutes.In this assay H. pylori is detected with the aid of specifi c antibodies against H. pylori. After the addition of the sample (feces diluted in buffer) color-labelled antibodies specifically bind to the bacteria if they are present in the sample. When these complexes migrate upward on the membrane by capillary action, they are captured with the aid of another specifi c antibody at the test result line region of the test. A red test result line is generated. If no bacteria are present, the color labelled antibody cannot bind at the test result line region. No red test result line is formed. So the presence of a colored test result line indicates a positive result, while its absence indicates a negative result. To serve as a procedural control, a colored line will always appear in the control line region indicating that proper volume of specimen has been added and membrane wicking has occurred.

SET-UP OF THE TEST DEVICE

The plastic case of the test cassette encloses the test strip. After addition of the sample into the round sample well the appropriate lines will form in the test result line region and the control line region of the rectangular test result window. To facilitate the reading of the result the region where the control line appears is marked with C. The region where, in case of a positive result, the test result will appear is marked with T.