Time to stop worrying about ABO incompatible cryoprecipitate transfusions in adults

See article on page 29–34, in this issue Although technically accurate, creates the perception that risk of RBC incompatibility and plasma are equal, when fact they not. ABO-incompatible RBCs never transfused (unless error), while transfusions form platelet, plasma, cryoprecipitate routinely performed. A lack understanding concept can have significant impacts patient care blood product availability as exquisitely highlighted by hesitancy non–transfusion specialists to accept COVID-19 convalescent plasma.1 The distinction what is considered acceptable compatibility clearly outlined current regulations. AABB Standard 5.15.1 specifies recipients receive “ABO group-compatible Red Blood Cell components, group specific Whole Blood, or low-titer O (for non–group-O for whose ABO unknown).”2 This means all containing compatible with recipient; however, whole will plasma. For potentially setting transfusions, 5.15.4 requires hospital transfusion services “have a policy concerning volumes incompatible antibodies.”2 How hospitals address standard mitigate hemolysis from varies widely.3 Current strategies include issuing only identical units, limiting volume using low titer units. platelets, additional options providing pooled blood–derived platelets suspended platelet additive solution, reduction washing units incompatible.4 major factor contributing need transfuse availability, being primary example. short shelf life makes maintaining an adequate inventory ABO-compatible impossible most institutions. Currently, approximately 19% United States incompatible, 10% recipients.5 Despite variability practice, severe hemolytic reactions remain uncommon events. annual US Food Drug Administration (FDA) fatality reports identify eight fatalities between fiscal years 2005 2018.6 Of these, seven involved high titers anti-A and/or anti-B recipients. consistent summary 25 published case describing 30 patients, which showed vast majority following occurred were AB patients.7 higher associated may be due tendency individuals make higher-titer compared B individuals.8 adoption fixed ratio massive protocols (MTPs) support bleeding emergencies has resulted increased patients unknown type, so ideally would used ensure always compatible. MTPs, require products available immediate release. It not possible maintain prethawed given 4% donors donor population AB.9 To meet demand avoid wastage many institutions unknown. In States, centers do limit amount situation anti-B.10 Kingdom, recommendations slightly more prescriptive: When unknown, ABO-nonidentical if it “low-titer” activity; should patients.11 Thus far, part MTPs been in-hospital early mortality, length stay, nonfatal complications.12-14 Annual FDA one was reported year 2007.15 service laboratory accidentally switched patientʼs ABO/Rh typing results another patient, led issued before second sample typed. Further details regarding recipient, circumstances surrounding transfusion, provided. As also increasing. 2017 National Collection Utilization Survey demonstrated 17% increase distribution 2015.16 There steady recent studies showing 2-fold number NHS Transplant 2015-2016 2003.11 trend likely continue, retrospective study reduced mortality hemorrhaging trauma patients.17 Cryoprecipitate usage management postpartum hemorrhage18 settings where thromboelastometry implemented.19-21 incorporation into but disproportionate wastage. because, unlike thawed 4 6 hours after thawing, precludes its reuse returned bank MTP.22, 23 Even wastage, allow strict adherence often presented same challenges until now. national shortages brought forefront reevaluate practices optimize management.24, timely report Hadjesfandiari et al TRANSFUSION highlights discrepancy practice guidelines provides compelling rationale realignment.26 standards transfusing antibodies (5.15.4). However, constitutes defined.2 typical adult dose very other transfused. example, apheresis unit pool platelets. contains 300 350 mL plasma.27 comparable unit, potential benefit diluting single high-titer pooling multiple each dose.7 recommended 15 20 mL/kg.28 If 283 ± mL,26 75-kg receiving mL/kg total 1132 60 mL. contrast, 10 (2 pools), 100 plasma.26 Therefore, 3-10× less 30-100× any dose. Simply based alone, reasonable assume low. We unaware cryoprecipitate. Consistent Canada indicate adults type.29 despite these standards, 14% willing use Canadian unknown.26 literature does adequately Strategies risk, such antibody titration, practical because frequent emergencies, delays postthaw titering could affect care. al26 evaluates levels provide evidence guidelines. Given concentrate proteins, there relatively shows significantly immunoglobulin M (IgM) concentrations no partitioning anti-A/B activity correlation IgM concentrations. addition, equivalent those corresponding (the difference cryosupernatant than two dilutions (±) expected precision reproducibility assay). Group did demonstrate B, similar seen platelets.8 Based bootstrap analysis, authors estimated probability worst-case scenario 1 3 million. limited small size (rare, identified), range general greater exceedingly combination already low-volume product, strong untitered, Use changes improve access supply remains challenge suppliers. By reducing divert production cryoprecipitate, Services 13%.26 clinical consequences evidenced some face supporting requiring exchange thrombotic thrombocytopenic purpura.30 Overall, adhering present critical opportunity individual our currently tenuous local supplies. declare conflict interest.