(Slightly paraphrased from the Guidance to the 34th Edition of AABB Standards for Blood Banks and Transfusion Services) AABB Standard 5.14.8 requires that there be 2 determinations of a recipients ABO group..... the first determination must be on a current sample and the second determination may be determined by one of the following methods: 1) comparison with previous records 2) testing a second sample collected at a time different from the first sample 3) retesting the same sample if the patient identification was verified at the time of sample collection using an electronic identification system. CAP standards (12/2024) Changes to Standards clarifies the requirement even further: "In the transfusion medicine checklist, TRM.40300 Historical Record Check says ABO, Rh, and antibody screen test results must be compared with results of the same tests recorded previously to detect discrepancies and identify patients requiring specially selected units. “New language was added to this existing requirement to clarify what is acceptable ABO and Rh historical records,” says Matthew Karafin, MD, MS, chair of the CAP Transfusion, Apheresis, and Cellular Therapy Committee and clinical professor of transfusion medicine services at the University of North Carolina at Chapel Hill. The revised requirement now says the acceptable ABO and Rh historical records for transfusion purposes are only those generated or entered by laboratory personnel into the health system’s laboratory information system and performed by an accredited lab or certified by the relevant government agency in its jurisdiction. “We learned that assessors have encountered facilities that were using blood types from other institutions, such as from Epic Care Everywhere,” Dr. Karafin says. “Moreover, we were made aware that blood typing information from these other institutions was sometimes being added by non-blood bank personnel, so we had concerns about the reliability of this information.” For patient safety, the CAP wants to ensure that the ABO and Rh used for transfusion are the ones that laboratory personnel have entered into an LIS. This “implies that a transfusion service reviewed the information and was responsible for its data entry,” Dr. Karafin says."