Statistical Classifier for Nucleic Acid Detection

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Solution Overview

Problem

Real-time PCR methods face challenges with false-negative and false-positive results due to samples falling into the 'grey area' where signals are near the minimum threshold, leading to unclassified samples and reduced sensitivity.

Innovation Solution

A method using a learning statistical classifier system to build a general linear classifier, which calculates weights from a training set of samples to classify the presence or absence of a target nucleic acid by measuring amplification-dependent parameters like fluorescence during PCR, minimizing unclassified samples through improved data analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a minimum threshold is set for signal classification, then classification simplicity is improved, but sensitivity is reduced due to grey area samples falling into unclassified pool

Engineering Contradiction:
Improveclassification simplicityVSAvoidsensitivity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transforms the classification approach by changing from a single threshold parameter to a multi-parameter statistical model. The general linear classifier uses multiple amplification-dependent parameters (Ct values, slope values, area under curve) combined with statistical distributions to create a more nuanced classification system that reduces grey area samples while maintaining operational simplicity through automated statistical processing

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a simple threshold-based classification is used, then device complexity is reduced, but measurement precision is worsened due to false-negative and false-positive results

Engineering Contradiction:
Improveclassification system complexityVSAvoiddetection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/threshold-based classification system with a statistical computing approach. Instead of using fixed thresholds that lead to false positives and negatives, the system uses statistical classifiers (linear discriminant analysis, quadratic discriminant analysis, support vector machines) that process multiple parameters through mathematical models to achieve higher precision while keeping the overall system complexity manageable through automation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If more statistical parameters are used in classification, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveclassification accuracyVSAvoidstatistical model complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal statistical framework that can handle multiple amplification-dependent parameters through a single general linear classifier structure. The classifier uses statistical distributions and mathematical models that can process various parameter combinations (Ct values, slope values, area under curve) uniformly, achieving high precision without proportionally increasing complexity through standardized statistical processing

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively reduces the number of unclassified samples by accurately classifying test samples as containing or not containing the target nucleic acid, enhancing the reliability of real-time PCR tests.

Implementation Method 1

contacting the test sample with a reaction mixture containing reagents necessary to amplify the target and the control nucleic acids by polymerase chain reaction (PCR) under conditions enabling PCR

Methodology Applied
Scientific EffectPolymerase chain reaction (PCR):

Implementation Method 2

measuring at least one amplification-dependent parameter for the target and the control nucleic acids to obtain a test set of data. In further variations of this embodiment, the amplification-dependent parameter is fluorescence detected during each cycle of amplification

Methodology Applied
Scientific EffectFluorescence detection: Fluorescence

Data Source

PatentUS9399794B2Method of detecting nucleic acid targets using a statistical classifier
Publication Date: 2016.07.26 ROCHE MOLECULAR SYSTEMS INC
  • US9399794B2 patent drawing
  • US9399794B2 patent drawing
  • US9399794B2 patent drawing

AI summary

A method of detecting a target nucleic acid in a test sample utilizes a learning statistical classifier system to build a general linear classifier based on an amplification-dependent parameter for the target and the control nucleic acids, in order to classify the test sample as containing or not containing the target nucleic acid.