Abstract: A device and method for verifying correct performance of an optical clinical assay system is provided.

Abstract: A test article for determining coagulation capability in a blood sample comprises a porous membrane having a coagulation initiator and substrate impregnated therein. The pore dimensions and composition of the membrane may be selected so that only blood plasma can pass into the interior of the membrane, where coagulation is initiated. Alternatively, the substrate may be selected to have an emission and/or excitation wavelength which is not absorbed by hemoglobin. The substrate is activated by a component of the coagulation pathway, typically thrombin, and produces a detectable signal upon activation. By utilizing membrane matrix materials which are substantially free from interference with the coagulation pathway, accurate results can be achieved.

Abstract: Assays for liquid analytes are performed on a bibulous matrix containing dried reagents which produce a visibly detectable reaction product. Application of liquid sample to the bibulous matrix is detected by measuring a drop in resistance across the matrix. A preferred test article for performing the method includes the matrix and a pair of spaced-apart electrodes in electrical contact with a reaction zone on the matrix. The test article is used in combination with a detection unit having means for probing the electrodes to determine when electrical resistance in the matrix has decreased. The assay methods and apparatus are particularly useful for performing enzyme assays where signal developed as a function of time is critical.

Abstract: Test articles comprise a solid phase membrane having dry thromboplastin immobilized thereon or within. The thromboplastin is substantially free from substances which might cause aberrant functioning intermediate transition states as the thromboplastin is rehydrated with liquid sample. Coagulation neutral agents which facilitate rehydration of the dry thromboplastin are also provided on the solid phase membrane.

Abstract: Assays for liquid analytes are performed on a bibulous matrix containing dried reagents which produce a visibly detectable reaction product. Application of liquid sample to the bibulous matrix is detected by measuring a drop in resistance across the matrix. A preferred test article for performing the method includes the matrix and a pair of spaced-apart electrodes in electrical contact with a reaction zone on the matrix. The test article is used in combination with a detection unit having means for probing the electrodes to determine when electrical resistance in the matrix has decreased. The assay methods and apparatus are particularly useful for performing enzyme assays where signal developed as a function of time is critical.