Abstract: An immunoassay method and apparatus for diagnosing FeLV-induced, persistent viremia is provided comprising combining a feline saliva sample conveniently obtained with a specially designed probe, with anti-p27 antibodies and detecting complex formation as indicative of the viremia. Preferably, the antibodies are bound to the probe for complex formation.

Abstract: The saliva test for feline leukemia virus (FeLV) employs a probe having an immunochemically sensitive member for collecting saliva from the oral cavity of a cat and employs ELISA reagents for the incubation of the probe and the development of color reactions to indicate the presence or absence of FeLV within the saliva sample collected onto the probe.

Abstract: The performance of immunoassays for the analysis of serum analytes can be significantly improved by the pretreatment of the sample. Analyte in serum samples is often complexed with serum antibody. Such analyte-antibody complexes can mask the analyte and interfere with analyte specific binding steps of many immunoassays. The serum pretreatment method employs pH dependent chaotropes to dissociate the analyte-antibody complexes in the serum. At low pH, the complexes become dissociated and the antibody becomes denatured. After the dissociation and denaturation of the serum antibody, the serum sample and the chaotrope, contained therein, are then neutralized. Since the serum antibody has been denatured, it does not re-associate with the analyte upon neutralization. After the neutralization step, serum sample can then be analyzed by an immunoassay, without interference from serum antibody. A serum pretreatment kit is essential to the employment of the serum pretreatment method.

Abstract: An immunoassay for assaying an antigenic substance (Ag) in a fluid. The immunoassay is the type which comprises contacting the fluid with at least one first entity selected from a group consisting of an antibody (Ab) to the Ag, a soluble, labeled antibody (L-Ab.sub.a) to the Ag, and an antibody (Ab.sub.b) to the Ag bound to a solid support (SC). The immunoassay is characterized in that the fluid is contacted with at least one additional entity selected from a group consisting of at least one different type of soluble, labeled antibody (L-Ab.sub.c) to the Ag, at least one different type of antibody (Ab.sub.d) bound to a solid carrier (SC.sub.1), and at least one different type of antibody (Ab.sub.e) to the Ag. The SC.sub.1 is selected from a group consisting of SC, at least one different solid carrier (SC.sub.2), and mixtures thereof (SC and SC.sub.2). Each type of L-Ab.sub.c, Ab.sub.d -SC.sub.1, and Ab.sub.e has a lower average affinity constant (K) for Ag than each respective K of L-Ab.sub.a, Ab.sub.

Abstract: A direct particle agglutination immunoassay for assaying an antigenic substance (Ag) in a fluid. The immunoassay is the type which comprises:(a) contacting the fluid with an antibody (Ab) coated particle (P) to agglutinate the Ab coated particles; and(b) detecting the presence of agglutination.The immunoassay is characterized in that the fluid is contacted with at least one additional entity selected from a group consisting of at least one different type of antibody (Ab.sub.a) coated particle (P.sub.1) and at least one different type of antibody (Ab.sub.b). The P.sub.1 is selected from a group consisting of P, at least one different particle (P.sub.2), and mixtures thereof (P and P.sub.2). Each type of Ab.sub.a -P.sub.1 and Ab.sub.b has a lower average affinity constant (K) for Ag than the K of Ab-P and the additional entity is present in an amount sufficient to avoid a high antigen false negative effect.Also, a reagent of the type comprising Ab-P.

Abstract: A device for handling and washing beads. The device is attachable to a test tube rack and includes a frame, a containing slide, and a capture slide. By manipulating the slides in various combinations of positions the beads may be added to, removed from, or separately washed apart from test tubes in the rack. Complete and easy washing of the beads may thus be accomplished.