The article examines the critical role of measurement uncertainty assessment in ensuring the reliability of the results of clinical diagnostic laboratories. A two-component measurement uncertainty model is analyzed which includes a component related to the traceability of results to the highest standards provided by the manufacturer of in vitro diagnostic systems and a component characterizing the reproducibility of measurements in a specific laboratory evaluated on the basis of in-laboratory quality control. The methodology for calculating the total measurement uncertainty is presented and its mandatory indication along with the analysis result in the format «Value ± measurement uncertainty (%)» which determines the range of possible values of the true value. The clinical importance of taking measurement uncertainty into account when interpreting laboratory data is emphasized. Using the example of the threshold value of anti-Muller hormone for deciding on the possibility of in vitro fertilization it is demonstrated how ignoring the uncertainty interval can lead to an erroneous refusal of treatment. The key challenges of the widespread introduction of measurement uncertainty into practice are noted: the need to maintain clinical diagnostic laboratories in a state of statistical manageability ensuring the reliability and completeness of data from in vitro diagnostic manufacturers modifying laboratory forms and most importantly training clinicians in the principles of interpreting results taking into account uncertainty. It is concluded that the integration of measurement uncertainty into routine laboratory reporting and clinical decision-making is a necessary condition for improving diagnostic quality minimizing errors and ensuring patient safety.

measurement uncertainty, clinical diagnostic laboratories, metrological traceability, presentation of results, diagnostic errors, in-laboratory quality control.