The quality of blood products obtained from two different autotransfusion devices (CATS- Fresenius and Sequestra 1000 - Medtronic) was tested in 27 patients undergoing elective orthopaedic surgery. Blood products provided from our institutional blood bank (n = 16) served as controls. Hemodiluted blood was separated into platelet poor plasma (PPP), platelet rich plasma (PRP), and packed red cells (PRC) and analysed for blood cell count, fibrinogen concentration, thromboplastin time, partial thromboplastin time, platelet aggregation and platelet recovery rate. Coagulation variables showed no differences between the CATS-group (n = 14) and the Sequestra 1000-group (n = 13). The volume of PRP was lower in the Sequestra 1000-group (45+/-3 ml vs. 89+/-1 ml, p<0.05), but hematocrit was higher (14.4+/-7.8% vs. 8.5+/-2.8%, p<0.05). PPP produced with CATS contained a higher concentration of white blood cells (0.6+/-0.2 Gpt/l vs. 0.1+/-0.01 Gpt/l, p<0.05) and thrombocytes (163+/-74 Gpt/l vs. 11+/-12 Gpt/l, p<0.05). Hematocrit of PRC was significantly higher in the CATS-group (73.8+/-2.0% vs. 69.0+/-6.5%, p<0.05). Blood products were of high quality in both groups and comparable to or superior than blood products provided from our institutional blood bank.