Adsorption type confirmatory assays
First Claim
1. An assay method for distinguishing between a small molecule analyte selected from the group consisting of LSD, LSD metabolites, and combinations thereof and an interfering substance in a sample comprising the steps of:
- a) preparing a reaction mixture comprising the sample, a hapten derivative that provides a signal and a detecting antibody that binds with the hapten derivative to yield a detectable signal in the assay, wherein the detecting antibody binds the hapten derivative in a manner that is specifically inhibitable by the analyte;
b) measuring the amount of the detecting antibody bound to the hapten derivative in step a);
c) treating the same sample or duplicate thereof with a neutralizing antibody in an amount sufficient to prevent the analyte but not all the interfering substance in the sample from binding the detecting antibody;
d) preparing a reaction mixture comprising the treated sample or duplicate, a hapten derivative that provides a signal, and a detecting antibody that binds with the hapten derivative to yield a detectable signal in the assay, wherein the detecting antibody binds the hapten derivative in a manner that is specifically inhibitable by the analyte;
e) measuring the amount of the detecting antibody bound to the hapten derivative in step d);
f) determining the difference in signal measured in step e) from step b); and
g) comparing the difference in signals in steps b) and e) to determine (i) the presence of analyte in the sample if the amount measured in step b) is significantly different from the amount measured in step e);
or (ii) the presence of interfering substance in the sample if the amount measured in step b) is not significantly different from the amount measured in step e).
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Accused Products
Abstract
The invention relates to an assay system for the improved detection of analytes, and the ability to distinguish them from cross-reacting substances. Samples giving a positive reaction in a direct assay test are treated with a neutralizing antibody that inhibits reactivity of the true analyte, but not the interfering substance. In adsorption type confirmatory assays, the neutralizing antibody is provided in an amount sufficient to adsorb the analyte but not all of the interfering substance. When retested in an immunoassay, the neutralized sample gives a negative result if it originally contained the true analyte. Samples giving a positive reaction in both the direct and confirmatory tests are marked as containing an interfering substance. The confirmatory assay easily distinguishes the true analyte and reduces the rate of false positives, even when the interfering substance is unknown and present at high concentration.
37 Citations
26 Claims
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1. An assay method for distinguishing between a small molecule analyte selected from the group consisting of LSD, LSD metabolites, and combinations thereof and an interfering substance in a sample comprising the steps of:
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a) preparing a reaction mixture comprising the sample, a hapten derivative that provides a signal and a detecting antibody that binds with the hapten derivative to yield a detectable signal in the assay, wherein the detecting antibody binds the hapten derivative in a manner that is specifically inhibitable by the analyte;
b) measuring the amount of the detecting antibody bound to the hapten derivative in step a);
c) treating the same sample or duplicate thereof with a neutralizing antibody in an amount sufficient to prevent the analyte but not all the interfering substance in the sample from binding the detecting antibody;
d) preparing a reaction mixture comprising the treated sample or duplicate, a hapten derivative that provides a signal, and a detecting antibody that binds with the hapten derivative to yield a detectable signal in the assay, wherein the detecting antibody binds the hapten derivative in a manner that is specifically inhibitable by the analyte;
e) measuring the amount of the detecting antibody bound to the hapten derivative in step d);
f) determining the difference in signal measured in step e) from step b); and
g) comparing the difference in signals in steps b) and e) to determine (i) the presence of analyte in the sample if the amount measured in step b) is significantly different from the amount measured in step e);
or (ii) the presence of interfering substance in the sample if the amount measured in step b) is not significantly different from the amount measured in step e).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 25)
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14. A kit for distinguishing between a small molecule analyte selected from the group consisting of LSD, LSD metabolites, and combinations thereof and an interfering substance in a sample in a confirmatory assay comprising:
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a) a detecting antibody that binds with the analyte to give a positive reaction in the assay;
b) a neutralizing antibody that binds with the analyte to prevent the analyte from giving a positive reaction in the assay; and
c) a hapten derivative that provides a signal;
wherein the detecting antibody binds the hapten derivative in a manner that is specifically inhibitable by the analyte and the interfering substance; and
the neutralizing antibody preferentially binds the analyte in comparison with the interfering substance; and
the neutralizing antibody is in an amount sufficient to prevent the analyte in the sample from binding the detecting antibody, but not sufficient to prevent all the interfering substance in the sample from binding the detecting antibody.- View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A kit for adapting an immunoassay for determining a small molecule analyte selected from the group consisting of LSD, LSD metabolites, and combinations thereof in a sample to permit distinguishing between the analyte and an interfering substance wherein the immunoassay is conducted with the following reagents:
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a) a detecting antibody that binds with the analyte to give a positive reaction in the assay; and
b) a hapten derivative that provides a signal;
wherein the detecting antibody binds the hapten derivative in a manner that is specifically inhibitable by the analyte and the interfering substance;
wherein the kit comprises a neutralizing antibody for the analyte to prevent the analyte from giving a positive reaction in the assay and in an amount sufficient to prevent the analyte in the sample from binding the detecting antibody, but not sufficient to prevent all the interfering substance in the sample from binding the detecting antibody. - View Dependent Claims (24, 26)
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Specification