A team of researchers at Washington University in St. Louis has developed Area Under the Curvature (AUCU), a data analysis method to improve the accuracy of homogeneous immunoassays (e.g., turbidimetric and nephelometric) while reducing costs and turn-around-times. AUCU can be easily integrated into existing machines and workflows to extend the analytical measurement range (AMR) of assays 10-fold and accurately quantify analyte concentrations without requiring additional sample dilutions.
Homogeneous immunoassays are widely used for clinical testing but suffer from nonlinearity due to antigen-excess, a phenomenon that limits the AMR and leads to significant quantification errors and false negative results when the concentration of analyte in a patient sample is high. Conventional methods to avoid this antigen-excess problem require repeated analysis with diluted samples, which wastes both time and expensive reagents. AUCU offers a faster, lower cost alternative that leverages reaction kinetics to extend the AMR in immunoassays. Importantly, this technique detects and corrects antigen-excess using data that are typically recorded by automated chemistry analyzers.
AUCU based calibration extends the AMR of a homogeneous immunoassay without sample dilution.
Stage of Research
The inventors validated AUCU on patient samples for two different clinical tests (serum free light chain and rheumatoid factor). They demonstrated a log-linear calibration curve in the zone of antigen excess extending the AMR by >10-fold.
Publication: Zaydman, M. A., Brestoff, J. R., Logsdon, N., & Gronowski, A. M. (2019). Kinetic Approach Extends the Analytical Measurement Range and Corrects Antigen Excess in Homogeneous Turbidimetric Immunoassays. Journal of Applied Laboratory Medicine, 4(2), 214-223.
- Clinical diagnostics: analysis of homogeneous immunoassays such as turbidimetric and nephelometric assays
- Instrument software: data analysis for turbidometric and nephelometric assays
- Improved test results:
- Extends AMR over 10-fold
- Quantifies analytes in samples with high concentration of antigen
- Reduces false negative rates and more accurately assesses disease state or response to therapy
- Lower costs and reduced turn-around-times: eliminates the need for sample dilution
- Easily integrated into existing machines and workflow: method uses data that is already routinely collected
Patents: Application pending
Related Web Links: Gronowski Profile