Immunochromatographic lateral flow strip test

The immunochromatographic lateral flow strip test is a one-step test that facilitates low-cost, rapid identification of various analytes at the point of care. We have developed lateral flow strip tests for the specific qualitative or semiquantitative detection of antigens, antibodies, and haptens, such as drug residues. Here, we describe in detail the preparation of three examples of the strip tests for detection of (a) the infectious bursal disease virus (b) Tricbinella specific antibodies, and (c) Clenbuterol residues in urine samples. 

Wang, X., K. Li, D. Shi, et al. 2007. Development of an Immunochromatographic lateral-flow test strip for rapid detection of sulfonamides in eggs and chicken muscles. J. Agric. Food Chem. 55 2072-2078. 

S. J., and Guo, J. Q. (2006) Development of an immunochromatographic lateral flow test strip for detection of -adrenergic agonist... 

The technology of the immunochromatographic test, also called lateral flow test or strip test, has been used for many years. However, its application to food safety, especially in mycotoxin testing is quite recent. The typical immunochromatographic test strip consists of a sample pad conjugate pad, membrane absorbent pad and adhesive backing. 

The first immunoassay performed in a capillary driven system was reported in 1978 [67]. Based on this technique, the commonly known over-the-counter pregnancy test was introduced into the market in the middle of the 80 s. Today, this microfluidic platform is commonly designated as a lateral flow test (LAT) [14]. Other terms are test strip , immunochromatographic strip , immunocapillary tests or sol particle immunoassay (SPIA) [68]. Astonishingly, hardly any publications from a microfluidic point of view or in terns of material classification exist, and apparently many company secrets are kept unpublished [69]. 

Lateral-flow immunoassays (LFTAs), also known as immunochromatographic test strips or dipsticks, are a form of rapid and portable immunoassay in which the test sample extract flows along a solid substrate via capillary action. The dipstick system is simple operationally, whereas the technology behind it is advanced and subtle. 

As a POC (point of care) device semi-quantitative flow-immunoassay methods for the detection of antibodies or antigens had been developed and are well establish in e.g. pregnancy tests. This format is also known as strip test, one step strip test, immunochromatographic test, rapid flow diagnostic, rapid immunoassay or lateral flow immunoassay (LFI). The label is anyway a colored colloidal particle. Additionally to metal colloids, carbon (black) and silica or latex (various colors) are in use. 

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