Lateral flow test

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The lateral flow test , also called lateral flow assay ( English for " lateral flow test ") is a biochemical method for the qualitative detection of substances with antibodies . The lateral flow test is a combination of thin layer chromatography and immunostaining . Due to the lower equipment cost compared to other immunassays , lateral flow tests are often used in the form of test strips , e.g. B. pregnancy test strips , drug test strips or rapid allergen tests .

principle

The sample to be examined is applied to the sample area ( English sample pad ) on a test strip made of porous paper or sintered polymer . After the addition of the solvent , the sample begins to spread over the test strip due to capillary forces (thin layer chromatography). The sample moves with the liquid to an area where there are dried immunoconjugates with salts and carbohydrates ( English conjugate pad ). The liquid dissolves the immunoconjugate, which allows it to bind to the molecules to be detected (the antigen ) in the sample, if any. The liquid moves further into the capillary area ( English capture pad ), where an antibody has been immobilized in a small section , which binds to another point on the surface of the molecule to be detected and thereby binds and accumulates it in this area while the liquid moves on. Due to the enrichment of the molecule to be detected, depending on the immunoconjugate z. B. a coloring , a fluorescent coloring or a magnetic marking . Usually there is also a second test strip that is used as a negative control without a sample and rules out false-positive results.

Individual evidence

  1. ↑ L. Kulinsky, Z. Noroozi, M. Madou: Present technology and future trends in point-of-care microfluidic diagnostics. In: Methods in molecular biology (Clifton, NJ). Volume 949, 2013, pp. 3-23, ISSN  1940-6029 . doi : 10.1007 / 978-1-62703-134-9_1 . PMID 23329432 .
  2. ↑ C. Rozand: Paper-based analytical devices for point-of-care infectious disease testing. In: European journal of clinical microbiology & infectious diseases: official publication of the European Society of Clinical Microbiology. Volume 33, Number 2, February 2014, pp. 147-156, ISSN  1435-4373 . doi : 10.1007 / s10096-013-1945-2 . PMID 23982665 .
  3. ^ A. St John, CP Price: Existing and Emerging Technologies for Point-of-Care Testing. In: The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists. Volume 35, Number 3, August 2014, pp. 155-167, ISSN  0159-8090 . PMID 25336761 . PMC 4204237 (free full text).
  4. ↑ AK Yetişen, MS Akram, CR Lowe: Paper-based microfluidic point-of-care diagnostic devices. In: Lab on a Chip . Volume 13, Number 12, June 2013, pp. 2210-2251, ISSN  1473-0189 . doi : 10.1039 / c3lc50169h . PMID 23652632 .