Setting up a washing control tool with a conductivity approach M. Farny*, CP. Mortier, B. Meges, R. Bessard Zentr Steril 2017; 25(3): 169–172. Detergent concentration during medical devices’ washing is currently monitored by measuring water’s conductivity. Conductivity threshold values, for high detergent concentration during washing phases and low residual concentrations at the end of rinsing, were empirically set. The purpose of this study is to confirm conductivity as a reliable monitoring parameter by checking the linear correlation between conductivity and detergent concentration, then by validating threshold values used to validate washing cycles. This study shows that conductivity is highly correlated to detergent concentration (R2>0.95). Furthermore, according to the results, we were able to refine conductivity threshold values daily used to validate washing cycles. Since its implementation, conductivity monitoring allowed us to detect two detergent mix-ups and one injection failure that otherwise wouldn’t have been detected. We are carrying on this study in order to validate the method with enzymatic products.