Chemistry: analytical and immunological testing – Involving an insoluble carrier for immobilizing immunochemicals
Reexamination Certificate
1998-01-05
2001-02-27
Le, Long V. (Department: 1641)
Chemistry: analytical and immunological testing
Involving an insoluble carrier for immobilizing immunochemicals
C435S004000, C435S007800, C435S007210, C435S007940, C435S025000, C435S028000, C435S805000, C435S810000, C435S967000, C435S970000, C435S971000, C435S287100, C435S287200, C435S287700, C435S287900, C436S169000, C436S510000, C436S514000, C436S518000, C436S523000, C436S525000, C436S531000, C436S534000, C436S805000, C436S810000, C436S065000, C436S818000, C422S051000, C422S051000, C422S051000
Reexamination Certificate
active
06194222
ABSTRACT:
FIELD OF THE INVENTION
This invention relates in part to the use of independent assay controls (IACs) for the optical communication between an assay device and an instrument in monitoring and performing assays, preferably immunoassays.
BACKGROUND OF THE INVENTION
The development of reliable methods for rapidly and simply measuring analytes in complex samples has become increasingly important. For example, the point of care testing in hospital emergency departments requires unskilled technicians to perform complex chemical and immunochemical assays to rapidly define the status of patients. The testing is usually performed by a nurse or an emergency room technician who are not trained as clinical chemists. The current practice of sending blood samples to the hospital laboratory is not feasible when the results are required within 30 min. The problem is thus that assay results are needed in a rapid time but the testing protocols, personnel and equipment available to the hospital emergency department are not compatible with this need. Other scenarios for obtaining rapid results through simple methods are in physicians offices, in patient homes and in field testing of pollutants and contaminants.
There is thus an unmet need for an immunoassay system that is simple, rapid and reliable.
Reliability in an immunoassay system is critical for the accurate measurement of the analyte. In an emergency room setting, the assay results can guide the physician in diagnosing and treating the patient. In a home setting, the assay result can, for example, help determine the amount and frequency of a therapeutic drug. In the field testing of pollutants and contaminants, the testing can define the extent of renovation or ground excavation needed to remove the contaminant.
Previous references regarding assay controls have not clearly defined parameters that require evaluation in assay devices. For instance, many publications simply provide examples of controls that determine the effect of non-specific binding. Some of these publications relate mainly to methods of controlling for non-specific binding and some references relate to devices that incorporate controls for non-specific binding. See, e.g., U.S. Pat. Nos. 4,533,629, 4,540,659, 4,843,000, 4,849,338, 5,342,759, 4,649,121, 4,558,013, 4,541,987, 4,472,353, and 4,099,886.
SUMMARY OF THE INVENTION
The disclosure provided herein teaches the novel use of independent assay controls (IACs) in assay devices. IAC results are not typically dependent upon assay results, however, results from one IAC may be dependent upon results from another IAC. For example, a change in a measurement in one IAC may be proportional to a change in a measurement in another IAC if the two IACs are dependent upon one another.
The term “IAC” as used herein can refer to any assay control measurement that is independent of an assay measurement. Some IACs may be independent with respect to one another and other IACs may be dependent with respect to one another. For example, a change in a first IAC measurement may occur while a change in a second IAC measurement may not occur when JACs are independent. In another example, a change in a first IAC measurement may correlate with a proportionate change in a third IAC measurement when IACs are dependent with respect to one another.
Once one or more IACs are measured, the IAC measurements can be utilized to correct assay measurements. These IACs can ensure that the results obtained from an assay detection system are accurate when assay conditions vary. Any of the IACs of the invention can be utilized to correct assay measurements. One IAC may be utilized to correct assay results, or multiple IACs may be utilized to correct assay results.
IAC for Determining the Rate of Flow
The term “rate of flow” as used herein can refer to the velocity at which a liquid solution travels through an assay apparatus. Rate of flow can be measured in terms of distance per unit time. Alternatively, rate of flow can be expressed in terms of an arbitrary unit or as a deviation from a mean value for rate of flow. A mean value for rate of flow can be determined in multiple experiments using different assay devices.
The term “assay device” as used herein can refer to any appropriate construction that allows the flow of fluids through chambers. For example, at least some chambers in an assay device may be tubes that can draw fluid by capillary action. Assay devices can be constructed from nearly any type of material, including propylene, polypropylene, and plastics, for example. An assay device may be placed in an apparatus described herein. The invention relates in part to any assay device capable of carrying out an IAC method defined herein. For example, if an IAC method requires that a second member of a binding pair (MBP) is associated with a solid phase of a diagnostic lane in an assay device, then one aspect of the invention features an assay device that comprises a second MBP associated with a solid phase in a diagnostic lane.
Thus in a first aspect, the invention features a method for determining a rate of flow of a solution through an assay device. The assay device comprises a reaction chamber and at least one diagnostic lane. The method comprises the following steps: Step (a): providing a first member of a binding pair (MBP) in the reaction chamber and a second MBP bound to a solid phase in the diagnostic lane. The first MBP comprises a label, and the first MBP and said second MBP do not appreciably bind to any IAC assay reagents in the assay device. However, the first MBP and the second MBP have specific binding affinity for one another. Step (b): detecting a signal in the diagnostic lane, where the signal is generated from the label. Step (c): determining the rate of flow of liquid through the assay device from the reaction chamber through the diagnostic lane from the amount of the signal in the diagnostic lane.
The term “reaction chamber” as used herein can refer to a portion of an assay device that contacts fluid before fluid reaches a diagnostic lane or diagnostic zone. A reaction chamber can be coextensively formed with an assay device, or alternatively, a reaction chamber can be a separate component with respect to an assay device. For example, samples and exogenously added reagents can be mixed in a test tube, which can serve as a reaction chamber. A portion or the entire contents of this test tube can then be introduced to an assay device. Fluids, biological samples, and reagents may be directly added to a reaction chamber.
The term “diagnostic lane” as used herein can refer to a portion of an assay device that harbors components comprising an IAC and an assay. A diagnostic lane may be as simple as a region allowing optical measurement of a signal. Alternatively, a diagnostic lane may comprise components that have specific binding affinity for molecules that comprise labels and molecules that comprise labels as a result of the assay process, such that binding events can be detected. In an example of an apparatus that includes capillary tubes, diagnostic lanes can embody capillary tubes aligned in parallel with respect to one dimension, or capillary tubes aligned in series with respect to one dimension.
The term “member of a binding pair (MBP)” as used herein can refer to any molecule or conglomerate of molecules that forms a complex with another molecule or conglomerate of molecules through specific binding events. Examples of MBPs are antibodies and their corresponding MBPs, as well as receptors and their corresponding MBPs. MBPs may be comprised of proteins, polypeptides, and/or small molecules, for example.
The term “do not appreciably bind” as used herein can refer to a phenomenon where interactions and/or lack of interactions between MBPs and other assay reagents do not significantly interfere with detection of a signal.
The term “assay reagents” as used herein can refer to any molecules located in an assay device or molecules exogenously added to a fluid introduced to an assay device used for measuring the presence or amount of an analyt
Anderberg Joseph M
Buechler Kenneth F.
McPherson Paul H.
Biosite Diagnostics, Inc.
Cook Lisa V.
Le Long V.
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