A medical apparatus (100) for extracorporeal blood treatment comprises a supportstructure (101) housing a hydraulic circuit (1) located above a liquid collectionzone (103) such that liquid losses from the hydraulic circuit can at least partiallyaccumulate at the liquid collection zone. A liquid sensor (108) detects presenceof any liquid in the liquid collection zone and operates in a distanced positionwith respect to the liquid collection zone (103).
