When and why is blood crossmatched?

Background and Objectives This study was undertaken to provide data relating to the timing of laboratory crossmatch procedures, and the source of requests for out of hours crossmatch, to support interpretation of error reports originating in the transfusion laboratory, received by the Serious Hazards of Transfusion haemovigilance scheme. Materials and Methods Data on the timing, origin and urgency of all crossmatch requests were collected in 34 hospitals in northern England over a 7‐day period in 2008. Additional data on clinical urgency were collected on crossmatches that were performed out of hours. Results Data were obtained on 2423 crossmatches, including 610 (25·2%) performed outside core hours. 30·3% of out of hours crossmatch requests were for transfusions that were set up outside 4 h of completion of the crossmatch. Conclusion 2008 Serious Hazards of Transfusion data showed that 29/39 (74%) of laboratory errors resulting in ‘wrong blood’ occurred out of hours whilst our audit shows that only 25% of crossmatch requests are made in that time period, suggesting that crossmatching performed outside core hours carries increased risks. The reason for increased risk of error needs further research, but 25 laboratories had only one member of staff working out of hours, often combining blood transfusion, haematology and coagulation work. A total of 25% of out of hours requests were not clinically urgent. Hospitals should develop policies to define indications for out of hours transfusion testing, empower laboratory staff to challenge inappropriate requests and ensure that staffing and expertise is appropriate for the workload at all times.