Abstract: An improved reagent and method for assay of total bilirubin in biological fluids utilizes diazo sulfanilic acid to convert bilirubin to azobilirubin which is then quantitatively measured. The improved reagent and method include the solvent accelerator tetramethylene sulfone. The use of tetramethylene sulfone as also allows the use of nonionic surfactants, obviating the need for serum blank correction in highly lipemic serum. Furthermore, the use of tetramethylene sulfone and nonionic surfactants renders the reagent mixture less viscous facilitating automated analysis.

Abstract: A test agent for the detection of coupling compounds in liquids is described, which essentially consists of an adsorbent matrix containing a diazonium salt as the reagent and a phosphonium salt to stabilize said test agent. Furthermore there is described a process for the preparation of said test agent.

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.