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Statistical inference for the within-device precision of quantitative measurements in assay validation
Jen-Pei Liu1, Li-Tien Lu, C T Liao
1Division of Biometry, Department of Agronomy, National Taiwan University, Taipei, Taiwan. jpliu@ntu.edu.tw
This study introduces a confidence interval approach for evaluating intermediate precision in assay validation, offering a more informative range than traditional point estimators. The generalized pivotal quantity method provides a robust confidence interval for within-device precision assessment.
Area of Science:
- Clinical Laboratory Science
- Biostatistics
- Analytical Chemistry
Background:
- Intermediate precision is crucial for assay validation.
- Current Clinical Laboratory Standard Institute (CLSI) EP5-A2 methods rely on point estimators for within-device precision.
- Confidence intervals offer a probabilistic range for precision, enhancing evaluation.
Purpose of the Study:
- To propose and evaluate a confidence interval approach for assessing within-device precision.
- To compare the proposed method with existing techniques under a two-stage nested random-effects model.
- To extend the confidence interval approach to include between-laboratories variation.
Main Methods:
- Application of generalized pivotal quantities (GPQ) to derive confidence intervals for within-device precision.
- Utilizing a two-stage nested random-effects model as per CLSI EP5-A2.
- Comparison with Satterthwaite's approximation and modified large sample (MLS) methods.
- Simulation study to assess coverage probability and interval length.
Main Results:
- The GPQ method provides a valid confidence interval for within-device precision.
- Comparison with existing methods using CLSI EP5-A2 data and simulation results.
- The proposed method is extendable to incorporate between-laboratories variation.
Conclusions:
- Confidence intervals offer a more comprehensive assessment of within-device precision than point estimators.
- The GPQ-based confidence interval is a reliable method for precision evaluation in assay validation.
- The approach can be extended for a more complete precision assessment including inter-laboratory variability.
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