Estimación de la incertidumbre y de la variabilidad total en el laboratorio clínico.

Background: ISO 15189 «Quality Management in the Medical Laboratory» has been developed for clinical laboratories evaluation, quality improvement and accreditation. This standard involves analytical process completely, from pre to post examination stage, giving importance to biological and analytical variability in addition to methodological traceability, test validation and the measurement of uncertainty and medical relevance. Objective: To clearly and briefly review and document uncertainty biostatistical principles that are applicable to the clinical laboratory including standard error, relative coefficient of variation, standard deviation index and total error as fundamental indicators of quality control. Material and methods: This is a review article of the scientific literature in which definitions, formulas and practical exercises on uncertainty indicators and total variability in analytical control of quality are documented. Results: It is clearly demonstrated that the utility of laboratory tests depend on multiple factors, which must be known, supervised and controlled as far as possible through analytical process. Discussion: The utility of these concepts depends on the routine application of quality indicators, which at the present time is highly feasible, since personal computers are already common tools in almost every clinical laboratory worldwide. Daily estimation of these formulas is actually quite simple leading to a dramatic positive impact on quality improvement of laboratory data when knowledge can be applied in order to control uncertainty. [ABSTRACT FROM AUTHOR]