A new method for the evaluation of measurement uncertainty in strict accordance with measurement model: Determination of total thyroxine in human serum by triple isotope dilution mass spectrometry

The rigorous and reasonable evaluation of uncertainty is crucial for the reliability of the results of a reference measurement procedure. A new uncertainty budget is proposed for uncertainty evaluation of a reference measurement procedure for total thyroxine in human serum based on isotope dilution liquid chromatography-mass spectrometry. In this work, a measurement model for uncertainty evaluation of triple isotope dilution-mass spectrometry was established. The propagation of uncertainties assigned to various input quantities was expressed in strict accordance with the measurement model. A detailed description of the uncertainty evaluation process for the measurement result of a specific serum is given, including the estimate of the input quantities and the determination of the combined standard uncertainty. The expanded uncertainty of the specific human serum (at coverage probability of 95%) was 4.8 nmol/L at the concentration level of 113.6 nmol/L.

Automated summary

The rigorous evaluation of uncertainty is crucial for reliable results in reference measurement procedures. This study proposes a new uncertainty budget for evaluating the uncertainty of total thyroxine in human serum using isotope dilution liquid chromatography-mass spectrometry. A measurement model for uncertainty evaluation of triple isotope dilution-mass spectrometry was established, and the propagation of uncertainties in input quantities was strictly followed. The detailed uncertainty evaluation process for a specific serum is described, including the estimation of input quantities and determination of combined standard uncertainty. The expanded uncertainty of the specific human serum (at a coverage probability of 95%) was determined to be 4.8 nmol/L at a concentration level of 113.6 nmol/L.