Research And Approach Of Helicobacter Pylori Antigen Test Based On Gold Immune Assay

Aims:(1)To approach the feasibility of diagnosing HP infection by detecting Helicobacter pylori antigens in different kinds of samples with dot colloidal gold immunity. (2)To provide experimental support for developing an easy-to-use kit of HP antigen test based on gold immune chromatography which can be used in the diagnosis of HP infection.Methods: (1) Gathering rabbit and human immune sera in which there was high titer anti-Hp-IgG confirmed by H.pylori-Ab-IgG test. Anti-HP IgG was purified and enriched by salt fractionation and affinity chromatography, and the colloidal gold was prepared by the method of Citrate trisodium reduction. Purified human anti-Hp IgG was linked with colloidal gold, which named gold-tagged-antibody. (2)As for the HP antigen detection, firstly fixed on nitrocellulose filters with purified rabbit anti-Hp IgG to form reaction board, secondly added the samples of gastric juices, feces or sera on reaction board respectively, thirdly dropped the gold-tagged-antibody on nitrocellulose filters. The red spot appeared on the nitrocellulose filter was considered positive result.Results: (1) The total 42 cases which considered true positive or true negative by the method of"gold standard HP test"were detected by dot immuno-gold HP-antigen test.The dot immuno-gold HP-antigen test for gastric juices was positive in 26 cases and negative in 16 cases. The positive rate and accuracy was 61.90%, 69.04%. The dot immuno-gold HP-antigen test for feces was positive in 27 cases and negative in 15 cases. The positive rate and accuracy was 64.29%, 57.14%. The dot immuno-gold HP-antigen test for sera was positive in 10 cases and negative in 32 cases. The positive rate and accuracy was 23.81%, 40.48%. (2) 60 patients were detected by both dot immuno-gold HP antigen test for gastric juices and urease test, the diagnostic corresponding rate between them was 61.67%. (3) 60 patients were detected by both dot immuno-gold HP antigen test for gastric juices and serologic H.pylori Ab-IgG test, the diagnostic corresponding rate between them was 65%.Conclusion: (1) Dot immuno-gold Hp antigen test for gastric juices can be used in the diagnosis of HP infection. (2) The accuracy of dot immuno-gold Hp antigen test for gastric juices is higher than that for feces and for sera. (3) The positive rate of dot immuno-gold HP antigen test for feces is higher than that for gastric juices and for sera, but the false positive rate is the highest in all too. (4) Dot immuno-gold Hp antigen test for gastric juice has well perspective because of its more merits such as convenient, rapid, less-lesion, no-rely-any-apparatus-to-read and avoiding- no-in-real-time of serologic anti-Hp test.