Patent ID: 6548309
Filing Date: 2003-04-15
Classification: B01L,G01N,Y10S

Abstract:
In a lateral flow assay for detecting, with or without quantifying, a dissolved component of a liquid test sample, which sample is obtained from a pool or flowing stream of liquid which also contains colloidal, semisolid and/or solid substances that, if contained in or carried with the liquid test sample, may interfere with, obscure or otherwise undesirably affect the result obtained, which assay is effected in a lateral flow test device that comprises a test strip having (i) a sample receiving site and (ii) a flow path positioned so that it directly contacts or is adapted to be placed in direct contact with the sample receiving site, along which flow path the liquid test sample, upon contact therewith, flows laterally by capillary action, wicking, sorption or another mechanism capable of promoting or inducing lateral liquid flow, the improvement which comprises(1) providing a flow path free of the presence of filter means and (2) in lieu of filtering the test sample prior to or at any stage of the assay, conducting a preassay procedure enabling delivery of only the liquid test sample directly to the sample receiving site in a condition free of the aforementioned colloidal, semisolid and/or solid substances, which procedure consists of: (a) providing a swab firmly affixed to a handle, which swab is a sorbent for liquid and is also capable of entrapping or otherwise isolating from the sorbed liquid any colloidal, semisolid and/or solid substances that are present in the original pool or flowing stream of liquid, which swab is formed from a fibrous material or a foamed pore material selected from among resins, rubbers and sponges; (b) immersing the swab in a pool or a flowing stream of liquid containing colloidal, semisolid and/or solid substances for a period of time sufficient to enable thorough wetting of the swab; (c) removing the wetted swab from the pool or flowing stream of liquid containing colloidal, semisolid and/or solid substances; and (d) bringing the wetted swab into contact with the sample receiving site of the test strip of the test device and expelling from the swab its sorbed liquid, which is the liquid test sample, directly on the sample receiving site while retaining any colloidal, semisolid and/or solid substances picked up by the swab in step (b) hereof on the swab.