Disclosed is an apparatus and method for determining the liquid level of salvaged blood in a blood collection reservoir (11) of an autologous blood transfusion system (20), comprising sensing means (10, 12) for periodically sensing the liquid level of the salvaged blood in said blood collection reservoir (11) and outputting corresponding signals, and determining means (2) for determining the liquid level of the salvaged blood in said blood collection reservoir (11) based on said output signal of said sensing means. The sensing means comprises a plurality of light emitters (12) disposed on a first side of said blood collection reservoir (11) at different height levels (L1-L9) for emitting light and a plurality of light receivers (10) disposed at said different height levels (L1-L9) on a second side of said blood collection reservoir (11) opposite to said first side for sensing light emitted by said light emitters (12) and transmitted through said blood collection reservoir (11). Parameters of the optical set-up used for detection and signal analysis may be adjusted individually and dynamically so that disturbing effects caused e.g. by absorptive films on the inner surface of the blood collection reservoir (11) may be identified and prevented to thereby enhance the reliability of signal detection and analysis.Linvention concerne un appareil et un procédé pour déterminer le niveau de liquide de sang récupéré dans un réservoir de collecte de sang (11) dun système de transfusion de sang autologue (20), comprenant un moyen de détection (10, 12) pour détecter périodiquement le niveau de liquide du sang récupéré dans ledit réservoir de collecte de sang (11) et délivrer des signaux correspondants, et un moyen de détermination (2) pour déterminer le niveau de liquide du sang récupéré dans ledit réservoir de collecte de sang (11) sur la base dudit signal de sortie dudit moyen de détection. Le moyen de détection comprend une pluralité démetteurs de lumière (12) disposés sur un
