Maximum surgical blood order schedules (MSBOS)

The available shelf life of a unit of blood decreases each time the unit is reserved or crossmatched for a patient who does not subsequently receive it.
When more blood is crossmatched and set aside for a patient than is required, it’s unavailable for other patients and increases the chance that the blood will expire before being used.
The adoption of policies such as the routine use of 'Group and screen' (wherever possible), a maximum surgical blood order schedule (MSBOS) and monitoring crossmatch-to-transfusion (C/T) ratios are all helpful in preventing unnecessary expiry of blood.
The MSBOS identifies the number of units typically required by 80% to 90% of the patients undergoing a specific surgical procedure where transfusion is likely.
This assists the clinician in ordering the appropriate number of units of blood for their patient.
The hospital transfusion laboratory, however, must give special consideration to patients with a positive antibody screen as the number of units shown in the MSBOS may not be appropriate in this context.
The ANZSBT guidelines provide a typical MSBOS. However, institutions should also consider their own particular circumstances, including the specific patient population or demographics (which may have special requirements) and local surgical practices and experience which may require the recommended MSBOS for a procedure to be adjusted.
Many large laboratories have moved to electronic crossmatching which allows timely and on demand issue of blood. Better stock management results in the laboratory needing to hold a smaller inventory and a reduction in wastage. If considering electronic crossmatching, the ANZSBT guidelines offer guidance.