- For many years, the crossmatch has served as the pretransfusion determinant of compatibility between recipient and donor. The majority of units of blood crossmatched for elective surgical procedures are not used and many antibodies detected in the crossmatch are not of clinical significance. Motivated by the need to eliminate testing that does not significantly enhance the provision of a safe product, the necessity for doing crossmatches has been questioned. Recent studies indicate that the substitution of the "group-and-screen" for the complete crossmatch represents an acceptable approach to the provision of blood for many elective surgical procedures. The benefit of this approach is significant: blood is utilized more efficiently and the blood bank has a reduction in workload. The risk is very minimal: only one of several thousand transfusions will be given to patients with previously undetected alloantibodies; and recent evidence indicates that such incompatibilities have little clinical impact.