Abstract: A reagent useful in the determination of an immunoreactive species comprises water-insoluble particles having tracer molecules associated therewith. Bound to the outer surface of the particles are: (i) receptor molecules which are reactive with the species, and (ii) molecules of a protein having a pI less than about 6, and which protein is not reactive with either the species or the receptor molecules. The weight ratio of the receptor molecules to the low pI protein molecules is from about 100:1 to about 1:10. This reagent is useful in agglutination and other immunological reactions. A method of preparing the reagent includes providing a suspension of the particles and contacting them with the receptor molecules and low pI protein so as to attach both to the particles. The protein is present in the suspension in an amount such that substantially all of it is attached to the particles.

Abstract: A test kit useful for the determination of Streptococcus A antigen comprises: (i) an immunoreactive reagent comprising either Streptococcus A antigen or antibodies attached to water-insoluble particles, (ii) a substrate having thereon a dried, binder-free coating of a first extraction reagent, (iii) an aqueous solution of a second extraction reagent, and (iv) a neutralizing solution. Both extraction reagents combine to provide nitrous acid. In addition, an extraction device includes a water-insoluble container having affixed therein the first extraction reagent and an applicator means for collecting and depositing a biological specimen within the container. The extraction device and test kit are useful to the determination of Streptococcus A antigen in a biological specimen.

Abstract: A windshield washer fluid supply comprising a bracket adapted to hold a conventional windshield washer solvent container in which the solvent is originally purchased. The invention also includes a plug which can be secured to the mouth of the solvent container which holds a tube extending into the solvent container and connected to the inlet of a fluid pump. The stopper permits use with solvent containers having different mouths and enables the container to be used with a submersible pump appropriately sized to fit within the container or used with a preexisting external fluid pump.