Urine-Based TB Antigen Detection via Simoa Immunoassay
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current diagnostic methods for Mycobacterium tuberculosis infection lack sensitivity and specificity, particularly in distinguishing active TB from latent infection and are affected by HIV status and BCG vaccination, leading to inadequate detection and treatment of TB cases.
Innovation Solution
Development of novel urine-based diagnostic assays using Single Molecule Array (Simoa) technology with bead-based immunoassays to quantify Mycobacterium tuberculosis antigens, providing high sensitivity and insensitivity to HIV status, allowing for accurate classification of active TB subjects and practical, cost-effective detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sputum smear microscopy is used for TB diagnosis, then specificity for active TB is improved, but sensitivity decreases to less than 70%
Solution Approach 1:
The patent replaces manual sputum smear microscopy with an automated urine-based immunoassay system using Simoa technology. This substitution eliminates manual interpretation variability while achieving superior sensitivity through automated single-molecule detection, directly resolving the contradiction between specificity and sensitivity in TB diagnosis.
Solution Approach 2:
The patent changes the diagnostic parameters by switching from detecting bacterial morphology in sputum to quantifying specific M. tuberculosis antigens (Ag85B and LAM) in urine at ultra-low concentrations. This parameter change enables detection of latent and paucibacillary cases that conventional microscopy misses, improving sensitivity while maintaining specificity through antigen-specific detection.
2Reliability
If nucleic acid amplification-based tests are used, then sensitivity is improved, but specificity for active TB infection decreases
Solution Approach 1:
The patent extracts and detects specific M. tuberculosis antigens (Ag85B and LAM) from complex urine samples using highly specific antibodies. This extraction approach allows detection of active infection markers while avoiding false positives from latent infection or BCG vaccination, resolving the sensitivity-specificity contradiction that plagues nucleic acid amplification tests.
3Reliability
If TST or IGRA tests are used, then detection of M. tb infection is improved, but ability to distinguish active TB from latent disease decreases
Solution Approach 1:
The patent replaces immune response-based detection (TST/IGRA) with direct antigen detection in urine using Simoa technology. This substitution allows quantification of active M. tuberculosis antigens versus latent infection markers, enabling differentiation of disease states while maintaining high detection sensitivity.
Solution Approach 2:
The patent changes from measuring host immune response parameters to measuring pathogen-derived antigen parameters directly in urine. This parameter change enables distinction between active and latent infection by detecting the presence and quantity of specific M. tuberculosis antigens, resolving the differentiation accuracy problem.
4Ease of operation
If conventional ELISA is used for antigen detection, then assay simplicity is maintained, but detection sensitivity decreases by 50 to 1000-fold
Solution Approach 1:
The patent replaces conventional ELISA with Simoa technology, substituting bulk antigen-antibody detection with single-molecule detection in femtoliter wells. This substitution maintains operational simplicity through automated bead-based assays while achieving 50-1000 fold sensitivity improvement through digital single-molecule counting.
Solution Approach 2:
The patent transitions from two-dimensional ELISA plate detection to three-dimensional single-molecule detection in femtoliter wells using bead-based capture objects. This dimensional change enables ultra-sensitive detection by confining single molecules in tiny volumes, achieving 50-1000 fold sensitivity improvement while maintaining assay simplicity.
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 assays significantly improve the detection sensitivity and specificity for TB, enabling reliable differentiation between active and latent TB, unaffected by HIV status, and are applicable in resource-limited settings, facilitating timely treatment and disease control.
Implementation Method 1
bead-based immunoassays to quantify Mycobacterium tuberculosis antigens
Data Source
AI summary
Methods and compositions are disclosed herein to detect Mycobacterium tuberculosis antigens, e.g., lipoarabinomannan (LAM) and/or Ag85B (Rv1886c), in a sample (e.g., a human urine sample) for diagnosis of tuberculosis. By developing ultrasensitive assays, both antigens are detected, with quantifiable differences levels in TB patients vs. non-TB controls.