Abstract: A slide for reacting a biological sample with reagents, and a method for using the same. The slide comprises a liquid-impervious top surface comprising glass, first portions of the surface having thereon a hydrophobic mask that repels an aqueous liquid, and second portions of the surface being completely free of any coverage by the mask so as to be wettable with an aqueous liquid, at least one of the other wettable second portions being totally isolated from the other wettable second portions by some of the mask, so that aqueous liquid will not flow from the one wettable portion to the another wettable portion until an overflow amount of aqueous liquid is added to the one wettable portion in an amount sufficient to bridge across the mask, and an absorbent material mounted at one side of the surface in position to receive liquid from the slide.

Abstract: A method of dispensing wash solution to separate free from bound labels in a slide immunorate assay. The method comprises dispensing wash first as separate drops spaced to allow complete absorption prior to the next drop, followed by a time at which the rate of dispensed wash exceeds the rate of fluid uptake of the slide, to form a continuous stream. The first phase of this wash method provides a more complete separation of bound from free under the dispense tip than occurs if only a continuous stream is used throughout.