Abstract: Biological fluid samples are deposited by methods that produce a uniform layer of the sample over a reagent-containing surface. In one embodiment, a nozzle having multiple openings is used to deposit a sample over the reagent-containing surface simultaneously. In an alternative embodiment, single droplets of the sample are deposited in a pattern on the surface, preferably in a sequence of parallel lines. The reaction between the biological sample and the reagents is read from a spectrographic image of the reagent-containing surface obtained by optical methods.

Abstract: Biological fluid samples are deposited by methods that produce a uniform layer of the sample over a reagent-containing surface. In one embodiment, a nozzle having multiple openings is used to deposit a sample over the reagent-containing surface simultaneously. In an alternative embodiment, single droplets of the sample are deposited in a pattern on the surface, preferably in a sequence of parallel lines. The reaction between the biological sample and the reagents is read from a spectrographic image of the reagent-containing surface obtained by optical methods.

Abstract: Biological fluid samples are deposited by methods that produce a uniform layer of the sample over a reagent-containing surface. In one embodiment, a nozzle having multiple openings is used to deposit a sample over the reagent-containing surface simultaneously. In an alternative embodiment, single droplets of the sample are deposited in a pattern on the surface, preferably in a sequence of parallel lines. The reaction between the biological sample and the reagents is read from a spectrographic image of the reagent-containing surface obtained by optical methods.

Abstract: Analytical results obtained with microfluidic devices are improved by providing structural features in areas containing dry supported reagents, the structural features directing the flow of a sample over the area in a predetermined uniform manner and facilitating the purging of air.

Abstract: Mixing of liquids in a microfluidic device is accomplished by dispensing the liquids into a first chamber to produce combined liquid. The liquids are thereafter discharged through at least one capillary from the first chamber into a second chamber for complete mixing.

Abstract: Biological fluid samples are deposited by methods that produce a uniform layer of the sample over a reagent-containing surface. In one embodiment, a nozzle having multiple openings is used to deposit a sample over the reagent-containing surface simultaneously. In an alternative embodiment, single droplets of the sample are deposited in a pattern on the surface, preferably in a sequence of parallel lines. The reaction between the biological sample and the reagents is read from a spectrographic image of the reagent-containing surface obtained by optical methods.

Abstract: Analytical results obtained with microfluidic devices are improved by providing structural features in areas containing dry supported reagents, the structural features directing the flow of a sample over the area in a predetermined uniform manner and facilitating the purging of air.

Abstract: Disclosed is a method for determining the concentration of an analyte in a sample of body fluid. The method involves contacting the body fluid sample with a test strip containing mobile, labeled specific binding partner for the analyte, through which strip the test fluid, analyte and any complex formed by interaction of the analyte and labeled specific binding partner therefore can flow by capillarity. The strip contains at least one zone for capture of the labeled specific binding partner and at least one separate zone for retention of the analyte/labeled specific binding partner complex. By determining the magnitude of the signal from the detectable label in the capture zone(s) and retention zone(s) and determining a final response signal by correlating signals using an algorithm and number of zones chosen in a manner that provides a final response signal best suited for the particular assay, the concentration of the analyte can be determined with greater precision.

Abstract: A fixed volume liquid transfer device defined by a small bore tube having an open end for collection of liquids and a plunger in the tube is disclosed. A piston is mounted around the open end and an air plug is mounted in the piston adjacent the open end. Liquid in a test tube is transferred to a testing site by inserting the transfer device into the test tube. As the piston contacts the liquid, the liquid is pumped into the tube. As the transfer device is inserted further, the air plug is actuated to balance air pressure across the piston. The device may then be withdrawn from the test tube and transported to a test site. At the test site, the plunger is depressed to expel the liquid into a testing device.

Abstract: Disclosed is a method for determining the concentration of an analyte in a fluid test medium by use of an immunochromatographic test strip through which the test fluid can flow by capillarity. The test strip has at least two capture bands and optionally one or more collection bands which capture labeled anti-analyte antibody to provide a detectable signal. The signals from the label is quantitatively detected in each of the bands to provide a pattern of signals which is unique to the concentration of analyte in the test fluid. The pattern of signals are mathematically combined to create a monotonous dose-response curve to thereby factor out the high analyte hook effect which can be present in this type of assay.

Abstract: Disclosed is an improvement to a sandwich type immunoassay in which there is immobilized to a solid support an antibody which is specific to an epitope of the analyte whose presence or concentration is being sought and a first labeled antibody which is specific to another epitope of the analyte. The improvement involves providing a second labeled antibody which is specific to the first labeled antibody to thereby form a chain of two or more labeled antibodies which results in amplification of the signal generated upon formation of the sandwich.