Abstract: A homogeneous specific binding assay device, a method for its preparation, and a method for its use in determining a ligand, such as antigen, hapten, or antibody, in, or the ligand binding capacity of, a liquid sample. The test device comprises a solid carrier member, such as a fibrous web matrix, e.g., paper, or a polymeric film or gel, incorporated with reagents for a homogeneous specific binding assay system which produces a detectable response, usually an electromagnetic radiation signal, that is a function of the presence or amount of the ligand in or the ligand binding capacity of the sample. Useful homogeneous specific binding assay systems include those involving enzyme substrate labels, enzyme prosthetic group labels, and enzyme labels. The detectable response preferably is a luminescent, fluorescent, spectrophotometric, or colorimetric response, which is measurable by visual observation or instrument means.

Abstract: A method for determining the presence of a ligand in, or the ligand binding capacity of a liquid test sample which includes the steps of (a) adding to the sample a conjugate of the ligand and a label, (b) contacting the sample with a test device containing reagents which in conjunction with the conjugate and ligand, are capable of producing a detectable response, and (c) measuring the response.

Abstract: A homogeneous specific binding assay element, a method for its preparation, and a method for its use in determining a ligand in or the ligand binding capacity of a liquid sample. The test element comprises a solid carrier incorporated with reagents for a homogeneous specific binding assay system which produces a detectable response, usually an electromagnetic radiation signal, that is a function of the presence or amount of the ligand in or the ligand binding capacity of the sample.

Abstract: A test kit for the determination of bilirubin in a test sample is disclosed. It comprises a reagent capable of producing a color change or other detectable response in the presence of bilirubin, and a test mat comprising finely divided silica gel. The kit is utilized by wetting the test mat with a portion of a liquid test sample suspected of containing bilirubin, contacting the wetted mat with the reagent, causing the reagent to at least partially wet the mat and observing the appearance of a color change or other detectable response.

Abstract: A stabilized composition comprising apoglucose oxidase is disclosed. In addition to the apoenzyme, a stabilizing agent comprising poly(vinyl alcohol), bovine serum albumin or mixtures thereof is included. The composition can also comprise, in addition to the apoenzyme and stabilizing agent, reagents for a homogeneous specific binding assay system capable of producing a detectable response which is a function of a ligand in, or the ligand binding capacity of a test sample, wherein the apoenzyme is itself one of the reagents in the assay system. The stabilized composition can be utilized in a test device for assaying a ligand in, or the ligand binding capacity of a liquid sample, whereby the device comprises a test device incorporated with the composition.

Abstract: A composition, device and method for determining the presence of a reducing agent, such as ascorbic acid, in a test sample are disclosed. The composition comprises certain thiazine and oxazine compounds which, in their oxidized state, are colored, but which become colorless when reduced by a reducing agent. The device comprises a carrier matrix incorporated with the composition, and the method comprises contacting a test sample with the composition device and observing any detectable response such as a color change.