Abstract: Provided are methods and devices for separating particulate analytes or aggregates of analytes from a fluid, after the separation medium of the device is saturated with the fluid. The endpoint indicating completion of the separation is determined by saturation; therefore, no precise metering of the fluid sample is necessary. The separated analyte of interest can be detected, quantitated or its migration measured in the separation medium. The measured property of the analyte can then be correlated with a parameter of interest. In some embodiments, the device can be marked to directly read the value of the parameter of interest. In one embodiment, the fluid is blood and the device includes a volumetric capillary reservoir for collecting the blood, a separation paper or indicator strip, and graduations for correlating the migration of red blood cells with hematocrit or hemoglobin concentration.

Abstract: The present invention concerns methods, compositions and apparatus for detection and/or determination of concentration of target molecules. In preferred embodiments the methods comprise allowing target molecules to form a complex with a first binding agent conjugated to a detection molecule and a second binding agent conjugated to a capture molecule, allowing the complex to further bind to an essentially uncharged polymer capable of binding to the capture agent, and performing a vertical gradient electrophoresis to separate the complex from unbound target, first and second binding agents and polymer. The intact complex is concentrated by electrophoresis at a stacking layer and the detection molecule is detected and/or quantified. Because the complex contains a very high mass to charge ratio, it becomes essentially immobile at the stacking layer, while unbound components migrate through the stacking layer and are separated from the complex.

Abstract: Methods and devices for analyzing fluid variables such as viscosity, surface tension, analyte concentration, and the presence of particulates or aggregates are provided. The devices analyze fluid variables by measuring cessation of fluid flow through the medium or a change in flow rate due to an inherent property of the fluid variable, or due to a modification of the fluid variable as the fluid migrates through the medium. The lateral flow devices measure relative rates of capillary flow down converging arms of a common element of porous media in which at least one of the arms has been modified by the addition of flow-modifying agents which affect the flow rate in response to the concentration of the analyte. The fluid fronts will converge at a position determined by their relative flow rates, which is thus indicative of a fluid variable, such as analyte concentration, in the sample fluid.