SUITABILITY OF PREADMISSION BLOOD-SAMPLES FOR PRETRANSFUSION TESTING IN ELECTIVE SURGERY

BACKGROUND: North American transfusion guidelines do not stipulate a t ime limit between drawing the specimen for pretransfusion testing and giving the transfusion to patients who have not received a transfusion or been pregnant in the preceding 3 months. British guidelines sugges t that separated plasma and serum can be stored at -30 degrees C for u p to 6 months, but they draw attention to the paucity of evidence conc erning the use of stored samples. In Australia, transfusion guidelines recommend a maximum of 10 days' validity for pretransfusion specimens , which requires the patient to present for pretransfusion testing wit hin 10 days or admission or to undergo retesting after admission, whic h in turn necessitates additional time in the hospital before operatio n. The study was performed to document the safety of using for pretran sfusion testing a blood sample collected more than 10 days before surg ery. STUDY DESIGN AND METHODS: Samples from 500 patients scheduled for elective surgery who had not been pregnant or received a transfusion in the previous 3 months were separately tested in blood group and ant ibody screens al an interval from 11 to 335 days before admission and again on admission. RESULTS: No clinically significant change was dete cted in the red cell antibody status of the paired samples of any pati ent. CONCLUSION: For patients who have not been transfused or pregnant in the previous 3 months, it is safe to crossmatch blood for transfus ion by using a sample collected well in advance of elective surgery an d stored at 30 degrees C.