Abstract: A receptor-based clinical or research competitive inhibition assay method for determining histamine in body or laboratory fluids is disclosed. A kit for carrying out the method is also described comprising an amount of histamine receptors sufficient to provide an excess of receptors for binding with the amount of histamine in the sample to be assayed, and an amount of a histamine-indicator conjugate sufficient to react with the resulting unbound histamine receptors present after reaction of the histamine sample with the histamine receptors.

Abstract: A method and kit for determining the total amount of an immunologically-reactive substance in a liquid sample containing interfering material capable of binding to an antigen. The method involves the steps of: (1) contacting a liquid sample containing or suspected of containing an antibody with the surface of a piezoelectric oscillator having a layer of antigen specific for the antibody attached thereto; (2) washing and drying the oscillator; (3) measuring the resonance frequency of the oscillator; (4) contacting said surface of the oscillator with a liquid reagent containing an excess amount of a substance specifically reactive with all of the antibody bound to the oscillator in step (1); (5) washing and drying the oscillator; and (6) measuring the change in resonance frequency of the oscillator form the first measurement whereby the amount of total antibody bound to the oscillator in step (1) is distinguished from the interfering material bound in step (1).

Abstract: A method and article for the determination of a particular subclass of antibody, e.g., IgA, IgE, IgM, etc., are disclosed. The method utilizes a piezoelectric oscillator having bound to the surface thereof an antigen specific for the antibody being determined. The antigen-coated oscillator is exposed to a solution containing an unknown amount of the antibody. After the antibody in the solution has attached to the antigen on the oscillator, the oscillator is exposed to a substance (sandwiching substance) which selectively binds to a specific subclass of the antibody being determined. The frequency of the oscillator is measured before and after exposure to the sandwiching substance. The change in frequency is related to the amount of the subclass of antibody bound to the oscillator, and the amount of the subclass of antibody in the solution can be quantified by reference to a standard curve.