Developers of membrane-based assays should have a firm grasp on the various factors that can influence protein binding—including those inherent in the materials and processing used for their tests.
The number of membrane-based rapid immunochromatographic devices on the market is continuing to increase at a very quick pace. Major factors that are contributing to this growth include improvements in conjugate technology and a growing understanding among product developers of the general design principles involved.
Although today's immunochromatographic devices come in a wide variety of designs with a diverse assortment of housings, most commercially available tests are based on one of two simple formats. The most common format is the lateral-flow or dipstick design, which has become familiar through its use in physician-office assays as well as in over-the-counter tests (e.g., Unipath's Clear Blue pregnancy test). A less widespread format is the flow-through or transverse-flow design, which requires greater operator skill and is therefore usually restricted to professional use (e.g., Medmira's rapid HIV screen).