Chemistry: analytical and immunological testing – Involving diffusion or migration of antigen or antibody
Reexamination Certificate
1998-12-31
2001-08-21
Chin, Christopher L. (Department: 1641)
Chemistry: analytical and immunological testing
Involving diffusion or migration of antigen or antibody
C422S051000, C422S051000, C422S051000, C422S051000, C422S068100, C422S069000, C422S070000, C435S004000, C435S287100, C435S287200, C435S287700, C435S287900, C435S810000, C435S970000, C435S971000, C436S518000, C436S805000, C436S810000
Reexamination Certificate
active
06277650
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved device for assaying a pre-selected analyte, such as an antigen, in a body fluid, such as urine.
BACKGROUND OF THE INVENTION
A variety of ligand-receptor assays have been developed to detect the presence of a preselected analyte in body fluid. Typically, these assays involve antibody-antigen interactions, synthetic conjugates comprising radioactively, enzymatically, spectroscopically, or visually observable tags, and specially designed reactor chambers. In most assays, there is a receptor (e.g., an antibody) that is specific for the pre-selected analyte (e.g., an antigen), and a means for detecting the presence and/or amount of a resulting receptor-analyte (e.g., antibody-antigen) complex. Most current assays are designed to make a quantitative determination, but in many circumstances all that is required is a qualitative result, i.e., a positive or negative signal. Examples of such qualitative assays include, for example, pregnancy tests, ovulation tests as well as a variety of other types of urine analysis. In these tests, visually observable signals such as the presence of agglutination of a color change are preferred.
The assays optimally are performed using single-step devices wherein the only step the user need perform prior to observation of the result is application of the sample to be assayed onto the device. Single-step devices, therefore, obviate the necessity of performing, subsequent to the application of the sample, a series of manipulations which may be time consuming and/or may introduce errors in the end result. Accordingly, several single-step devices, for example those described in International Application Nos. WO 88/08534, published Nov. 3, 1988, have been developed and are commercially available.
The single-step device described in International Application Published No. WO 88/08534 comprises a hollow casing containing a porous assay material communicating with the exterior of the casing via a fluid sample receiving member. During operation, the user applies the fluid test sample onto the fluid sample receiving member protruding out of the casing. Thereafter, the fluid sample while traversing the carrier material enters the casing and moves to a capture region disposed upon the carrier material. The capture region comprises a means for binding a pre-selected analyte. When the fluid sample reaches the capture region, assuming that the fluid sample contains the analyte, the analyte binds to the capture region. The bound analyte subsequently can be visualized within the capture region.
It has been found, however, that invalid test results may arise from the use of single-step devices, particularly devices wherein the fluid sample is applied directly from a fluid stream through a urine inlet port defined by the casing onto assay material enclosed therein.
SUMMARY OF THE INVENTION
Accordingly, with the problems in the prior art in mind, it is an object of the present invention to provide an improved single-step detection device for reliably detecting the presence of a pre-selected analyte within a body fluid, when the body fluid, i.e., urine, is applied directly from a fluid stream, i.e., a urine stream, onto assay material disposed within device.
It is another object of the invention to provide a method for detecting a pre-selected analyte using a single-step device of the type described herein.
It is yet another object of the invention to provide a method for producing a single-step detection device of the type described herein.
Yet another object of the invention is to provide a method and apparatus for permitting a user, after applying a fluid sample onto assay material, to immediately know a test is working rather than waiting a substantial time for a test result, if any, to appear in a viewing window of the detection device.
The present invention provides a rapid, sensitive and more reliable device and method for detecting the presence of analytes in a fluid stream. The use of the present device and method provide a system for measuring the presence of a pre-selected analyte in body fluid, specifically urine, which involves a minimal number of procedural steps, and reproducibly yields reliable results even when used by untrained persons.
It has been discovered that during the use of single-step devices, particularly devices wherein the sample of fluid to be assayed is applied directly from a stream of fluid onto assay material enclosed within the device casing, false or otherwise invalid results may arise following hydraulic pressure induced flooding of assay material. The incidence of flooding impairs the reliability, and therefore the commercial value of the test kit. Accordingly, the single-step device and method of the instant invention utilize an improved device casing that minimizes hydraulic pressure induced flooding of the assay material located therein, for thereby substantially increasing the reliability of the test result. More specifically, it has been discovered that introduction of drainage vents in the casing dramatically improves the reliability of the test kit and virtually eliminates the incidence of flooding.
In its broadest aspect, the invention provides a device having an outer casing and an assay material disposed within the casing for detecting the presence of an analyte in a urine stream. The assay material defines a capture region for binding the analyte. The outer casing defines the following features which include a hollow housing enclosing the assay material; a urine inlet port to permit urine applied directly from a urine stream to enter the casing and contact the assay material disposed within the casing; a window spaced apart from the urine inlet port for viewing the capture region; and at least one drainage vent to permit excess urine entering the casing through the urine inlet port to exit the casing thereby to minimize pressure induced flooding of the casing.
In a preferred embodiment, the assay material comprises a sorptive material defining a urine sample application region spaced apart from the capture region. The sorptive material permits the sorptive transport of urine between the urine sample application region and the capture region. Therefore, when urine from a urine stream is directed through the urine inlet port onto the urine sample application region the analyte in the urine moves by sorptive transport from the urine application region to the capture region, whereupon the analyte binds to the capture region.
In another embodiment, the device casing defines three drainage vents spaced about the urine inlet port to permit urine entering the casing via the urine inlet port to exit the casing. The drainage vents, therefore, minimize the build up of urine within the casing and thereby inhibit hydraulic pressure induced flooding of the assay material disposed therein. In another embodiment, the window for viewing the capture region is located on a side of the device casing opposite the urine inlet port.
In another embodiment, the device further comprises a rib member defining a dam positioned within the casing to inhibit hydraulically driven urine from flooding the casing. The rib member may either be defined by an inner surface of the casing formed during the production of the casing or may be a separate component inserted into the device during assembly.
In a preferred aspect, the invention provides a device having an outer casing and an assay material disposed within the casing for detecting the presence of an analyte in a urine stream. The outer casing defining the following features which include: a hollow housing for receiving the assay material; a urine inlet port at a proximal end of the casing to permit urine applied directly from a urine stream to enter the casing; a window at a distal end of the casing for viewing a capture region on the assay material; and at least one drainage vent to permit excess urine entering the casing through the urine inlet port to exit the casing thereby to minimize hydraulic pressure induced flooding of the casing. T
Boyle Mary Beth
Cheng Yea-Shun
Nazareth Albert R.
Carter-Wallace Inc.
Chin Christopher L.
Watov Kenneth
Watov & Kipnes P.C.
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