Abstract: The efficiency and accuracy of one-step lateral flow assays can be improved by employing more efficient binding between participants in labeling and capture. Thus, in addition to analyte/anti-analyte interactions, specific binding is achieved through members of an irrelevant specific binding pair. Also included within the invention is a format wherein unlabeled competitor for analyte serves as a gatekeeper in the capture zone, competing with analyte for labeled anti-analyte, which analyte will be captured in a detecting portion of a capture zone.

Abstract: A test device and method for determining the presence or absence of one or more analytes in a fluid sample, the test device including a support or member bearing a mark thereon, and a matrix or member containing a capture zone. In operation, an observation area in the test device becomes transparent, thereby allowing the user to view a mark that is present on a support that is disposed beneath the observation area. Typically, the mark on the underlying support is configured as a minus (−) sign. In the absence of analyte in the sample, the test device presents a negative result as a minus (−) signal. In the presence of analyte in the sample, however, the mark operates in concert with a perpendicular test line on the observation area to present a positive result as a plus (+) signal that is visible to the user.

Abstract: One-step enzyme immunoassays in which enzyme-antibody conjugate or label and enzyme substrate are separated until separation of bound and free enzyme conjugate or label is complete. This separation is accomplished by using variable flow paths, immobilization of substrate at the test line, placement of substrate in a sac or association with a particle label, enzyme product chemical capture, delay zone dissolution and protected enzyme substrates.

Abstract: A method and device for detecting the presence, absence or amount of an analyte in a whole blood sample is disclosed. The device comprises four zones, a sample receiving zone, a labeling zone, a capture zone and an absorbent zone. The sample receiving zone contains an irreversibly immobilized reagent that allows for removal of substantially all red blood cells from the whole blood sample. Flow through the device is via capillary migration and all of the dissolved or dispersed components in the sample flow at substantially equal rates and with relatively unimpaired flow through the device. The method involves the use of the device for detection of analyte in a whole blood sample.

Abstract: A sensitive and specific antigen preparation for the detection of Helicobacter pylori in biological samples is disclosed. The preparation uses a range of antigens derived from size exclusion chromatography of detergent-solubilized H. pylori cells. Serological assays such as ELISA, latex agglutination, and rapid EIA assays utilizing the improved antigen preparation, and a kit for use in these serological assays are also disclosed.

Abstract: A sensitive and specific antigen preparation for the detection of Helicobacter pylori in biological samples is disclosed. The preparation uses a range of antigens derived from size exclusion chromatography of detergent-solubilized H. pylori cells. Serological assays such as ELISA, latex agglutination, and rapid EIA assays utilizing the improved antigen preparation, and a kit for use in these serological assays are also disclosed.

Abstract: The present invention provides devices and methods for the detection of creatinine in biological fluids using lateral flow methodologies. The invention is particularly useful in providing one step creatinine assays for correcting urinary steroid hormone assays.

Abstract: Methods and devices for distinguishing between normal and abnormal pregnancies are provided. The methods rely on determining the concentration of progesterone or progesterone metabolite in a patient sample, where a concentration above a threshold value is indicative of a normal pregnancy. Preferably, the concentration of hCG is determined simultaneously, where an hCG concentration above a threshold value provides confirmation that the individual being tested is pregnant. An exemplary test device comprises a lateral flow membrane having zones for capturing label in response to the progesterone and hCG concentrations, respectively. Visible label is accumulated when the hCG concentration exceeds the threshold value but is absent when the progesterone concentration exceeds the threshold value.

Abstract: A device for detecting the presence of substances, particularly biological materials, contained in a liquid sample is formed of a series of layers of film materials. A first film has a cut-out which forms an upper reservoir for receiving the liquid sample. A first reagent is provided in the upper reservoir capable of reacting with a substance possibly contained in the liquid sample. A first membrane is situated at the base of the upper reservoir and is made of a material which is temporarily impermeable so that the liquid sample is temporarily retained in the upper reservoir in contact with the first reagent, but after awhile the membrane becomes permeable and allows the liquid to pass. A second film has a cut-out which forms a median reservoir positioned for receiving the liquid passing through the first membrane. A second reagent is provided in the median reservoir capable of reacting with a predetermined substance.

Abstract: A lateral flow assay device for detecting the presence of Chlamydia antigen in patient's samples comprises a flow matrix including a labelling zone and a capture zone. Labelling complex comprising antibodies specific for an epitope on the lipopolysaccharide antigen of Chlamydia is present within the labelling zone. Immobilized antibody specific for the same or another epitope of the lipopolysaccharide antigen of Chlamydia is located in the capture zone. The sample containing the Chlamydia antigen will flow first through the labelling zone, where it complexes with the labelling complex, and then to the capture zone, where it is captured by the immobilized antibody. Chlamydia antigen may be extracted from a patient sample, such as a endocervical swab, by first extracting the antigen in a strong base followed by neutralization with a zwitterionic detergent and a blocking protein present in a zwitterionic buffer.

Abstract: A particularly efficient design for a nonbibulous lateral flow one step assay for an analyte in a biological sample is disclosed. In the improved device of the invention, three zones which are in nonbibulous lateral flow contact are employed: a sample receiving zone, a labeling zone, and a capture zone. The sample containing analyte is carried through the labeling zone and interacts with an assay label comprising visible moieties, preferably particles, which are coupled to specific binding reagent for analyte or to a competitor with analyte for a capture reagent. The flow continues into the capture zone where the visible moieties to which analyte or competitor are coupled are captured. Excess fluid is absorbed into an absorbent zone in contact with the capture zone. A positive result is obtained by visualizing the visible moieties in the capture zone.

Abstract: A particularly efficient design for a nonbibulous lateral flow one step assay for an analyte in a biological sample is disclosed. In the improved device of the invention, three zones which are in nonbibulous lateral flow contact are employed: a sample receiving zone, a labeling zone, and a capture zone. The sample containing analyte is carried through the labeling zone and interacts with an assay label comprising visible moieties, preferably particles, which are coupled to specific binding reagent for analyte or to a competitor with analyte for a capture reagent. The flow continues into the capture zone where the visible moieties to which analyte or competitor are coupled are captured. Excess fluid is absorbed into an absorbent zone in contact with the capture zone. A positive result is obtained by visualizing the visible moieties in the capture zone.

Abstract: A device for assaying biological fluids for molecules contained therein comprising a container, material situated in the container for absorbing fluid and in communication with an antibody or antigen impregnated matrix, wherein the matrix is accessible to the exterior of the container through a funnel shaped aperture in the roof of the container. Further features include a chemical drying agent associated with the container for absorbing moisture, thereby preventing inactivation of the assay reagents, and a filter situated above the antibody or antigen impregnated matrix, and in communication with the matrix through the aperture in the roof of the container. The filter removes interfering substances present in the biological fluids and provides protein blocking agents to the matrix material for decreasing the background of the assay.

Abstract: The present invention provides specific binding solid phase assay methods and kits for the detection of the presence or absence of a microorganism by directly staining the microorganism and specifically capturing the stained microorganism on a solid support. The methods find particular utility in the detection of Candida. The methods may simultaneously detect the presence or absence of multiple microorganisms.

Abstract: A "one step" device for the detection of analytein clinical assays is disclosed. A visible label comprising a visible moiety and a ligand that binds to or competes with analyte is contained in a fluid conducting membrane or prefilter; and the analyte and associated ligand are conducted by the flow of sample into a detection zone. The detection zone contains a capture reagent that binds to label or to analyte bound to label.

Abstract: An assay for determining the presence of a threshold concentration of an analyte in a sample comprises first reacting the sample with an amount of anti-analyte selected to reduce the free analyte to a marginally detectable concentration. The sample is then contacted with anti-analyte immobilized on a test region or indicator zone on a solid phase, whereby the residual free analyte may be bound. The binding of free analyte to immobilized anti-analyte is detected by a variety of techniques to indicate the presence of the threshold concentration. By employing limited amounts of anti-analyte on the solid phase, the change between maximum binding of label and no binding of label will be responsive to very small changes in the analyte concentration originally present in the sample.

Abstract: Polysaccharide antigens characteristic of Group A or B Streptococci are extracted for use in immunodiagnostic assays by a simplified method. The method involves the use of two dried reagents, sodium nitrite and Tris base, and a liquid reagent, acetic acid.

Abstract: An improved one-step immunochromatographic assay which involves the binding of a predetermined amount of analyte to an antibody, enabling the control of the assay sensitivity, is disclosed. The system is especially useful as a controlled sensitivity fecal occult blood assay. Antibodies to a desired analyte, present at a predetermined concentration, are deposited on the sample pad of the reaction unit. The antibody binds analyte present in the sample, up to a threshold amount. Analyte which is present in the sample at a level above the threshold amount proceeds unbound through the sample pad and onto a membrane, where it reacts with an antibody-coated latex and a second, immobilized antibody to generate a positive signal.

Abstract: The present invention provides devices, methods and kits for assessing fertility potential of semen samples. Semen samples may be assayed by the present invention to identify those samples having more than 20.times.10.sup.6 motile sperm per milliliter, a concentration associated with fertile samples.

Abstract: The present invention relates generally to test articles and assays for the detection of analytes in biological fluid samples. More particularly, the present invention relates to test articles an assays which employ dyed microorganisms as visual labels to detect suspected analytes.