How long do crossmatch samples need to be retained by the blood bank?  

Any examples are for illustrative purposes only.

Blood banks must retain samples of both the transfused unit(s) and recipient blood for at least seven days following transfusion. Further, guidelines state patient samples for antibody screening and compatibility testing are acceptable to use for a maximum of three (3) days following the date of collection, at which time a new patient sample would be necessary^. As such, a transfusion may be given up to three days after the sample's original collection date. In order to meet the requirement to retain samples for at least seven days after transfusion, samples would need to be retained for at least 10 days after the original collection date.

^If a patient's history is known and they have definitely not been transfused or pregnant in the preceding three months, protocols can be established for frozen retention of the patient's serum for a longer period.