water impermeable regions iii formation of strips of water permeable material within a sheet of the material by cutting regions from a sheet of the material in order to form multiple channels iv printing e g by silk screen of a water permeable material e g nitrocellulose or other material used to make diagnostic and filter membranes in emulsion or other fluid form onto a water impermeable surface to create channels of the water permeable material v multiple water permeable channels comprised of any material and produced by any method vi a single water permeable channel or strip comprised of any material and produced by any method in a single channel device there would be one or more detection zones vii a channel s of free space within a water impermeable structure forming a capillary in which liquid may flow by capillary action this technique is sometimes referred to as a u201c capillary flow u201d diagnostic device in a single channel device there would be one or more detection zones and viii other types of channel in use a fresh sample applied at 1 is moved via capillary action into the primary reagent conduit the filter paper may be hydrophilic over at least part of its area to restrict and or concentrate the flow of sample along the primary conduit 2 the primary reagent.