In this paper, we discuss perspectives of adopting procedures of metrology, the science of measurements, into sustainability assessments. We present an overview of general concepts of system theory, sustainability, and sustainability metrics. We use these concepts together with the Guide to the Expression of Uncertainty in Measurement (GUM) metrological approach to include estimation of uncertainties and sensitivity analysis in the model framework to construct aggregated sustainability indicators proposed by Santos and Brandi. To illustrate the method, we apply Canberra distance to study the sustainability of the integration and logistic infrastructure dimension of the biodiesel supply chain in Brazil and Germany. Sustainability has been embodied into government, industries and corporations' policies through standards, conformity assessment, and metrology. This increases the need for sound measurements to address sustainability. To perform sensitivity analysis, we propose an expression to evaluate changes in the sustainability index due to variations in a given indicator, generalizing the linear approximation of the GUM framework. We concluded that metrological procedures can be applied to estimate uncertainties of sustainability systems and their components. Adopting metrological procedures may be an important step to harmonize approaches involving measurements in sustainability systems. Sensitivity analysis provides information about the influence on the sustainability index due to variations of indicators from sustainability systems.