Evaluation of Assigned-Value Uncertainty for Complex Calibrator Value Assignment Processes: A Prealbumin Example

Abstract

Background: Errors of calibrator-assigned values lead to errors in the testing of patient samples. The ability to estimate the uncertainties of calibrator-assigned values and other variables minimizes errors in testing processes. International Organization of Standardization guidelines provide simple equations for the estimation of calibrator uncertainty with simple value-assignment processes, but other methods are needed to estimate uncertainty in complex processes. Methods: We estimated the assigned-value uncertainty with a Monte Carlo computer simulation of a complex value-assignment process, based on a formalized description of the process, with measurement parameters estimated experimentally. This method was applied to study uncertainty of a multilevel calibrator value assignment for a prealbumin immunoassay. Results:The simulation results showed that the component of the uncertainty added by the process of value transfer from the reference material CRM470 to the calibrator is smaller than that of the reference material itself (<0.8% vs 3.7%). Varying the process parameters in the simulation model allowed for optimizing the process, while keeping the added uncertainty small. The patient result uncertainty caused by the calibrator uncertainty was also found to be small. Conclusions: This method of estimating uncertainty is a powerful tool that allows for estimation of calibrator uncertainty for optimization of various value assignment processes, with a reduced number of measurements and reagent costs, while satisfying the requirements to uncertainty. The new method expands and

Optimizing Available Tools for Achieving Result Standardization: Value Added by Joint Committee on Traceability in Laboratory Medicine (JCTLM)

“…It should be noted that using the described approach to estimate the MU contribution of the RMP may yield a worst-case MU estimate for the RMP contribution to the combined MU for the assigned value of a commercial calibrator. When IVD manufacturers work with an RLS to assign values to a panel of human samples, the robustness of the value transfer design and protocol may be enhanced by inclusion of multiple independent samples that may result in a reduction in MU propagation from the RMP (24).…”

Application of the adaptive Monte Carlo method for uncertainty evaluation in the determination of total testosterone in human serum by triple isotope dilution mass spectrometry

“…The MCM has also be a research hotspot in uncertainty evaluation in the fields of physical and chemical metrology in recent 20 years, especially with the application of computer and commercial software [12][13][14][15][16][17][18]. There are only a few reports of the implementation in clinical medical measurement [19,20].…”