Disclosed is an organ care system for ex-vivo organ care without causing substantial haemolysis denaturing of proteins. The organ care system comprises a blood product heater including an inlet tube for flowing a blood product into the blood product heater where the inlet tube has an inside cross-sectional area and an inside cross-sectional shape and an outlet tube for flowing the blood product out of the blood product heater where the outlet tube has an inside cross-sectional area and an inside cross-sectional shape. A channel extends between the inlet tube and the outlet tube where the channel has a first flow channel plate comprising a first substantially bioinert blood product contacting surface for providing direct contact with the blood product flowing through the channel； and a second flow channel plate comprising a second substantially bioinert blood product contacting surface for providing direct contact with the blood product flowing through the channel. A first heater is thermally coupled to the first flow channel plate. A pump circulates the blood product to an organ being preserved. The channel has an inside cross-sectional area substantially equal to at least one of the inside cross-sectional area of the inlet tube or the inside cross-sectional area of the outlet tube, however the channel has an inside cross-sectional shape that is different from at least one of the inside cross-sectional shape of the inlet tube or the inside cross-sectional shape of the outlet tube.
