From maximum surgical blood ordering schedule to unlimited computer crossmatching: evolution of blood transfusion for surgical patients at a tertiary hospital in Hong Kong.

The maximum surgical blood ordering schedule (MSBOS) was developed to permit efficient use of blood stocks and reduce blood wastage due to outdating. Success of the MSBOS required full cooperation between surgeons, anaesthetists, blood bankers and house officers. However, clinical staff sometimes disregarded the system or distrusted the ability of the laboratory to provide blood in an emergency. This led to frustration and wastage of laboratory staff effort. We developed a computer crossmatch system that could overcome the shortcomings of the MSBOS. The advantages of this system are reported.