AABB/ICTMG International Platelet Transfusion Guidelines

The Association for the Advancement of Blood and Biotherapies (AABB) and the International Collaboration for Transfusion Medicine Guidelines (ICTMG) recently published an international clinical practice guideline on the use of platelet transfusions.¹ Platelet transfusion is a common procedure with approximately 2.2 million performed annually in the United States.² The guideline notes that the decision to transfuse platelets should consider both potential benefits (preventing or treating bleeding) and harms (transfusion-related adverse events).

The new guidelines were the result of evaluating the available evidence of the impact of platelet transfusions on patient outcomes by a panel of experts, methodologists, and patient partners. The panel identified 21 randomized trials comparing restrictive to liberal platelet transfusion strategies. Restrictive strategies in randomized trials used either lower platelet count values as thresholds, lower platelet doses, or early platelet transfusions. Overall, the evidence did not show clear benefits using liberal strategies when considering the most important outcomes as voted by the panel: reducing mortality or bleeding. For this reason, the panel made several recommendations in favor of restrictive strategies to reduce transfusion-related adverse events and to help maintain platelet supply for patients most likely to benefit (e.g., those with major bleeding).

Although the evidence showed a pattern of no clear benefit with liberal strategies (evidence certainty: high/moderate overall), the exact restrictive strategies recommended varied depending on the patient population. The panel made a total of 11 recommendations. Four recommendations were strong and based on high/moderate certainty evidence, whereas the remaining seven recommendations were conditional and based on low/very low certainty evidence for those specific populations. For conditional recommendations, it is particularly important to consider the individual patient’s values and preferences in making the decision to transfuse.

For non-bleeding patients in the hematology/oncology setting with hypoproliferative thrombocytopenia (HPT), the panel made a strong recommendation to transfuse platelets when the count was <10×10³/μL for those actively receiving chemotherapy or undergoing allogeneic stem cell transplant. However, for patients with HPT undergoing autologous stem cell transplant or with aplastic anemia, the panel made a conditional recommendation for no prophylaxis.

For patients with consumptive thrombocytopenia in the absence of major bleeding, the panel made restrictive recommendations for preterm neonates (strong), patients with dengue (strong), and adults with non-dengue-related consumptive thrombocytopenia (conditional).

Several recommendations were made in a variety of procedural settings. For patients undergoing lumbar puncture, a strong recommendation was made for a restrictive strategy (transfuse when count <20×10³/μL) because the evidence showed the risk of spinal hematoma was near zero among patients with counts <50×10³/μL. Put another way, a very large number of patients would need to be transfused liberally to prevent one spinal hematoma, and numerous patients would be expected to experience harm due to adverse events (e.g., transfusion-associated circulatory overload). Other recommendations in procedural settings were conditional and specific platelet count thresholds chosen generally attempted to account for bleeding risk of procedure types (e.g., lower versus higher). Two conditional recommendations, in non-thrombocytopenic patients undergoing cardiovascular surgery and patients with nonoperative intracranial hemorrhage with platelet counts >100×10³/μL including those taking anti-platelet agents, were geared toward avoiding unnecessary platelet transfusions in patients with relatively higher platelet counts based on the lack of evidence of benefit and, in some cases, the possibility of harm.

In summary, a recent international platelet transfusion guideline recommended restrictive strategies due to a lack of evidence of clear benefit when using liberal strategies. The unequivocal benefits with restrictive strategies extend to avoiding transfusion reactions, maintaining adequate supply, and (lastly) avoiding unnecessary healthcare costs. There are several priorities for future research related to clinical use of platelets. There is a need for additional randomized trials, particularly in settings where current evidence is of lower certainty. We also need an improved understanding of how best to implement evidence-based transfusion guidelines to support improved patient outcomes. In the United States, we administer 50% more platelet transfusions per person than in the United Kingdom and Canada.^2-4 Platelet supply is challenging to maintain given short shelf life, and platelet transfusions come with the highest risk of adverse events compared with other blood products. Implementation of restrictive strategies would be expected to improve outcomes by reducing adverse events and ensuring adequate availability for those most likely to benefit.

References:

1. Metcalf RA, Nahirniak S, Guyatt G, et al. Platelet Transfusion: 2025 AABB and ICTMG International Clinical Practice Guidelines. JAMA. 2025;334;(7):606-17. doi:10.1001/jama.2025.7529
2. McDavid K, Lien R, Chavez Ortiz J, et al. Have we reached a new baseline for blood collection and transfusion in the United States? National Blood Collection and Utilization Survey, 2023. Transfusion. Published online March 11, 2025. doi:10.1111/trf.18187
3. Nahirniak, Susan (Faculty of Medicine & Dentistry – Laboratory Medicine & Pathology Dept., University of Alberta, Edmonton, AB). Teleconference. 2025.
4. Stanworth, Simon (Radcliffe Dept. of Medicine, University of Oxford, Oxford, GB). Teleconference. 2025.