مقایسه ایمنی سنجی جریان جانبی (LIFA) جهت شناسایی عفونت هلیکوباکتر پیلوری

ABSTRACT Comparison of the lateral flow immunoassays (LFIA) for the diagnosis of Helicobacter pylori infection

It is well known that half of the world populations are infected with Helicobacter pylori mainly those of the developing countries (Kimmel et al., 2000). The majority of subjects however are asymptomatic and only few percentages develop peptic ulceration that might progress to gastric cancer (Sipponen, 1998; Sipponen and Marshall, 2000). The diagnosis of H. pylori infection in such patients is an important approach for the selection of therapy and for the follow up of eradication success. H. pylori infection can be diagnosed by invasive and non-invasive techniques. The invasive technique (endoscopy) relies on the collection of gastric biopsy specimen to detect H. pylori by rapid urease test, culture, PCR and/or histopathology (Ricci et al., 2007). This is a time consuming and expensive approach unlike the non-invasive tests such as 13C-urea breath test (UBT), stool antigen test and serology tests. The UBT and stool antigen tests detect the presence of H. pylori and are called active tests. Serology however (e.g. the ELISA test) detects anti-H. pylori antibodies which is an indicator for H.

pylori exposure and is called passive test (Sciortino, 1993; Kimmel et al., 2000; Ricci et al., 2007). The lateral flow immunoassay (LFIA) is another alternative for the ELISA test used in serological and fecal diagnosis of H. pylori infection. It is intended particularly for a quick diagnosis and as a single use supporting test at a health care unit. Kato et al. (2004) compared the widely used stool antigen ELISA test with the lateral flow stool antigen test and reported that the later showed good specificity and sensitivity in the detection of H. pylori infection in children. The LFIA is an immunochromatographic assay (ICA) that is commercially available for a wide array of targets such as infectious agents (bacteria, viruses) (Nakasone et al., 2007; Cui et al., 2008; Kawatsu et al., 2008; Peng et al., 2008), hormones (Posthuma-Trumpie et al., 2008), drugs (Zhang et al., 2006; Zhu et al., 2008; Xie et al., 2009), pesticides (Zhou et al., 2004; Guo et al., 2009) and mycotoxins (Kolosova et al., 2007; Wang et al., 2007b). A visual qualitative (on/off) signal is enough for most applications. The best-known and first developed (LFIA) was the pregnancy test for the detection of human chorionic gonadotropin (hCG) hormone in urine sample (Leuvering et al., 1980; van Amerongen et al., 1993). Several investigators have also developed their own lateral flow test strips for the detection of various target molecules (Tanaka et al., 2006; Kolosova et al., 2007; Wang et al., 2007a, 2011; Chiao et al., 2008; Kawatsu et al., 2008; Peng et al., 2008; Zhao et al., 2008; Li et al., 2009; Xie et al., 2009; Xu et al., 2009; Omidfar et al., 2010; Yu et al., 2011).

In general the lateral flow test strips have the advantages of being rapid (2–5 min), easy to use (selferforming), cost effective, portable, highly sensitive and specific. They do not require complicated equipment and technical expertise that are critical parameters for point-of-care, and have long shelf life at room temperature (12–24 months) (Posthuma-Trumpie et al., 2009; Ngom et al., 2010). The aim of this article is to review the components and the principles of lateral flow immunoassay (LFIA) devices and to compare the currently available rapid H. pylori commercial test devices.