Abstract: A diagnostic test kit for detecting an analyte residing in a test sample is provided. The kit employs a lateral flow device that contains a membrane. A metering channel is formed in the membrane that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay. Such a metering channel is particularly effective for embodiments in which the test sample has a relatively low volume, such as less than about 100 microliters, in some embodiments from about 0.5 to about 25 microliters, and in some embodiments, from about 1 to about 10 microliters. For example, whole blood drops obtained from patients with a lancet typically have a volume of less than about 3 microliters. Despite their low volume, the present inventors have discovered that the blood drops may still be accurately analyzed for the presence of an analyte using lateral flow detection techniques.

Abstract: A method for controlling fluid flow in an assay device that employs a membrane is provided. Specifically, one or more recessed regions are formed in the membrane by applying a solvent treatment thereto. The solvent treatment is selected based on its particular dissolving capacity for the material used to form the membrane. For example, an alcohol-based solvent, such as methanol, may be used as a solvent for nitrocellulose membranes. Upon contact with the solvent treatment, a recessed region is formed that may serve a variety of different functions relating to flow control. In one particular embodiment, the recessed region may function as a metering channel that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay.

Abstract: A method for controlling fluid flow in an assay device that employs a membrane is provided. Specifically, one or more recessed regions are formed in the membrane by applying a solvent treatment thereto. The solvent treatment is selected based on its particular dissolving capacity for the material used to form the membrane. For example, an alcohol-based solvent, such as methanol, may be used as a solvent for nitrocellulose membranes. Upon contact with the solvent treatment, a recessed region is formed that may serve a variety of different functions relating to flow control. In one particular embodiment, the recessed region may function as a metering channel that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay.

Abstract: A method for controlling fluid flow in an assay device that employs a membrane is provided. Specifically, one or more recessed regions are formed in the membrane by applying a solvent treatment thereto. The solvent treatment is selected based on its particular dissolving capacity for the material used to form the membrane. For example, an alcohol-based solvent, such as methanol, may be used as a solvent for nitrocellulose membranes. Upon contact with the solvent treatment, a recessed region is formed that may serve a variety of different functions relating to flow control. In one particular embodiment, the recessed region may function as a metering channel that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay.

Abstract: A diagnostic test kit for detecting an analyte residing in a test sample is provided. The kit employs a lateral flow device that contains a membrane. A metering channel is formed in the membrane that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay. Such a metering channel is particularly effective for embodiments in which the test sample has a relatively low volume, such as less than about 100 microliters, in some embodiments from about 0.5 to about 25 microliters, and in some embodiments, from about 1 to about 10 microliters. For example, whole blood drops obtained from patients with a lancet typically have a volume of less than about 3 microliters. Despite their low volume, the present inventors have discovered that the blood drops may still be accurately analyzed for the presence of an analyte using lateral flow detection techniques.

Abstract: A diagnostic test kit for detecting an analyte residing in a test sample is provided. The kit employs a lateral flow device that contains a membrane. A metering channel is formed in the membrane that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay. Such a metering channel is particularly effective for embodiments in which the test sample has a relatively low volume, such as less than about 100 microliters, in some embodiments less than about 25 microliters, and in some embodiments, less than about 10 microliters. For example, whole blood drops obtained from patients with a lancet from low-pain areas (due to reduced nerve endings than finger), such as the forearm, thigh, or other alternate sites, may have a volume of from about 0.1 to about 5 microliters. Despite their low volume, the present inventors have discovered that the blood drops may still be accurately analyzed for the presence of an analyte using lateral flow detection techniques.

Abstract: A system that employs transmission-based detection techniques to determine the presence or concentration of an analyte within a test sample is provided. Specifically, the optical detection system contains a chromatographic-based assay device that is positioned in the electromagnetic radiation path defined between an illumination source and detector. To enhance the sensitivity and signal-to-noise ratio of the system without significantly increasing costs, the distance between the illumination source and/or detector and the assay device is minimized. The illumination source and/or detector may also be positioned directly adjacent to the assay device. In addition, the system may be selectively controlled to reduce reliance on external optical components, such as optical filters or diffusers.

Abstract: A microfluidic assay device for determining the presence or absence of an analyte within a fluid test sample is provided. The present invention provides a technique for achieving continuous flow in a microfluidic device by using at least one input channel, an analysis zone, and a plurality of wicking channels disposed about the perimeter of the analysis zone. In one embodiment, for example, the wicking channels extend radially from the analysis zone. As a result of the particular configuration of the microfluidic device, an assay may performed in a “single step” without the need for active forces, such as a pressure source, electrokinetic force, etc., to induce flow of the fluid test sample through the device. Likewise, flow rate is controlled so that the dwell time of the fluid test sample within the analysis zone is long enough to allow for the desired reactions and/or detection.

Abstract: There is provided a lateral flow assay device for detecting the presence or quantity of an analyte residing in a test sample where the lateral flow assay device has a porous membrane in communication with a wicking pad. The porous membrane has a detection zone which has a chromophore configured to chemically react with an analyte or a secondary trigger or a reaction product from the analyte and a trigger generating reagent(s), to generate a visually detectible signal. Additional chrmophore zones may be located downstream from the first chrmophore zone to generate signals of varying color. Scavenging zones may be included between chromophore zones to attenuate the signal by reacting with the analyte without generating a visually detectable signal.

Abstract: A flow-through assay device capable of detecting the presence or quantity of an analyte of interest is provided. The device is in communication with an electrochemical biosensor that utilizes detection and calibration working electrodes that communicate with affinity reagents, such as redox mediators and capture ligands. For instance, capture ligands that are specific binding members for the analyte of interest may be applied to the detection electrode to serve as the primary location for detection of the analyte. The calibration working electrode may be used to calibrate the detection working electrode for any intrinsic background current not generated by the reagents of the biosensor system. Moreover, capture ligands that are non-specific binding members for the analyte of interest may also be applied to the calibration electrode.