Unlike other blood components demand for platelet components appears to be increasing in several countries around the world (1). An ageing population, an increase in the incidence of haematological malignancies, and changes to the management of haematological malignancies are likely to be the major reasons for the rise in demand for platelet components. Since 1990, the number of haematopoietic stem cell transplants performed in Europe has risen from 4,200 to over 47,000 annually (2).

More than 50% of all platelet transfusions are indicated for patients with haematological conditions, such as those with acute myeloid leukemia and those undergoing stem cell transplantation. The other common indications are cardiac surgery (10%), oncology (6.5%), critical care (5%) and liver disease (2.5%) (3,4).

Prophylactic versus therapeutic-only platelet transfusions

International guidelines recommend that platelets transfusions are given to people with reversible bone marrow failure to reduce the risk of spontaneous bleeding when the platelet count is <10x109/L. A Cochrane systematic review in 2015 on patients with haematological malignancies found that overall prophylactic platelet transfusions appeared to reduce the number of bleeding events and days with significant bleeding (5). However, the benefit from prophylactic platelet transfusions differed between treatment groups with patients undergoing autologous HSCT deriving no significant benefit (6). In patients with haematological malignancies bleeding frequently occurs despite prophylactic platelet transfusions, and other risk factors for bleeding such as fever and duration of thrombocytopenia should be considered (7,8).

There is little evidence to guide practice for patients with chronic bone marrow failure. International guidelines which consider these patients recommend either a therapeutic-only strategy (9,10) or prophylaxis below a count of 5x109/L (11). BSH Guidelines for the diagnosis and management of adult myelodysplastic syndromes advise a no prophylaxis strategy and include in this group people taking low dose oral chemotherapy or azacitidine (12).

In critical care settings, the optimal management of platelet transfusions may vary based on underlying clinical diagnoses (13,14). A RCT involving patients with dengue haemorrhagic fever demonstrated that prophylactic platelet transfusions did not effectively prevent bleeding and were associated with adverse effects, including anaphylaxis (15).

Different platelet transfusion doses for prophylactic platelet transfusions

A systematic review identified seven RCTs comparing different platelet transfusion doses, revealing no significant difference in the incidence of clinically significant bleeding episodes between low-dose and intermediate-dose groups, low-dose and high-dose groups, or high-dose and intermediate-dose groups (16). Studies have shown that the incidence of TRAEs is notably higher with high-dose transfusions (16,17). Common adverse events include febrile nonhemolytic transfusion reactions and allergic reactions, which can complicate patient management (18). 
The standard dose for prophylactic platelet transfusions is generally considered to be around 3x1011 platelets per transfusion. This is often administered as one apheresis unit or a pool of 4 to 5 pooled whole blood-derived platelet units for an average-sized adult (19).

Different platelet transfusion thresholds for prophylactic platelet transfusions

A systematic review identified three RCTs comparing different platelet transfusion thresholds in patients with haematological malignancies (20). Two compared a threshold of 20x109/L vs. 10x109/L, whereas the third compared a threshold of 30x109/L vs. 10x109/L. The findings indicated no significant difference in clinically significant bleeding episodes between the lower threshold (10x109/L) and higher threshold groups, with a risk ratio (RR) of 1.35 and a 95% confidence interval (CI) of 0.95 to 1.90, categorised as low-quality evidence. However, this meta-analysis may not be sufficiently powered to detect a 50% increase in bleeding risk, suggesting the need for further research to establish more definitive conclusions regarding optimal transfusion thresholds. There has been a suggestion that platelet transfusion thresholds should be lowered below 10x109/L, but current platelet count measurement is not accurate enough to support this change (21). No randomised studies in adult patients have assessed the use of other transfusion thresholds, such as platelet mass, absolute immature platelet number or immature platelet fraction. 

Neonates admitted to the neonatal intensive care unit (NICU) frequently become thrombocytopenic and intracranial haemorrhage (ICH) is a major concern. Recent guidelines on neonatal platelet transfusion emphasize a more restrictive approach based on emerging evidence. The consensus suggests that platelet transfusions should be considered for neonates with severe thrombocytopenia, particularly when platelet counts fall below 25x109/L, especially in non-bleeding preterm infants (22). This threshold aims to balance the risks of bleeding with the potential complications of transfusion. Recent studies have indicated a significant shift towards more restrictive platelet transfusion practices in neonatal care. The PlaNeT-2 trial demonstrated that liberal platelet transfusion practices were associated with increased neonatal mortality (23). This trial has influenced many neonatal intensive care units (NICUs) to adopt more conservative transfusion thresholds, typically around 25 to 30 x109/L, rather than the previously common threshold of 50x109/L. A recent systematic review indicated that restrictive transfusion thresholds are now being recommended to prevent unnecessary transfusions, which can expose neonates to potential risks such as transfusion-related infections and immune reactions (24).

Therapeutic platelet transfusions

Recent studies have highlighted the complexities surrounding the effectiveness of platelet transfusions in patients with thrombocytopenia who are actively bleeding (4). Current guidelines recommend that platelet transfusions should be tailoured to the individual patient’s needs, considering factors such as the underlying cause of thrombocytopenia, the severity of bleeding, and the patient's overall clinical condition. This individualised approach is essential to optimize the benefits of transfusions while minimising potential complications. Please refer for details to [ISBT section on major haemorrhage].

Key recommendations based on the evidence from RCTs
  • Give prophylactic platelet transfusions (platelet transfusions to patients who do not have clinically significant bleeding [WHO grade 0 or 1] and do not require a procedure) to patients with reversible bone marrow failure receiving intensive chemotherapy or undergoing allogeneic HSCT to maintain a platelet count at or above 10x109/L
  • Do not give high dose platelet transfusions routinely for prophylactic platelet transfusions

References

  1. Estcourt L. Why has demand for platelet components increased? A review. Transfusion Medicine. 2014;24(5):260-8.
  2. Passweg JR, Baldomero H, Gratwohl A, Bregni M, Cesaro S, Dreger P, et al. The EBMT activity survey: 1990-2010. Bone Marrow Transplant. 2012;47(7):906-23.
  3. Charlton A, Wallis J, Robertson J, Watson D, Iqbal A, Tinegate H. Where did platelets go in 2012? A survey of platelet transfusion practice in the north of England. Transfusion Medicine. 2014;24:213-8.
  4. Mo A, Wood E, McQuilten Z. Platelet transfusion. Curr Opin Hematol. 2025;32(1):14-21.
  5. Crighton G, Estcourt L, Wood E, Stanworth S, Trivella M, Doree C, et al. A therapeutic-only versus prophylactic platelet transfusion strategy for preventing bleeding in patients with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation. Cochrane Database of Systematic Reviews. 2015;2015(9).
  6. Stanworth S, Estcourt LJ, Llewelyn C, Murphy MF, Wood EM, for the TOPPS study investigators. Impact of prophylactic platelet transfusions on bleeding events in patients with hematologic malignancies: a sub-group analysis of a randomized trial. Transfusion. 2014;54(10):2385–93.
  7. Stanworth SJ, Hudson CL, Estcourt LJ, Johnson RJ, Wood EM. Risk of bleeding and use of platelet transfusions in patients with hematological malignancies: recurrent event analysis. Haematologica. 2015.
  8. Webert K, Cook RJ, Sigouin CS, Rebulla P, Heddle NM. The risk of bleeding in thrombocytopenic patients with acute myeloid leukemia. Haematologica. 2006;91(11):1530-7.
  9. Kaufman RM, Djulbegovic B, Gernsheimer T, Kleinman S, Tinmouth AT, Capocelli KE, et al. Platelet transfusion: a clinical practice guideline from the AABB. Ann Intern Med. 2015;162(3):205-13.
  10. Liumbruno G, Bennardello F, Lattanzio A, Piccoli P, Rossetti G. Recommendations for the transfusion of plasma and platelets. Blood Transfus. 2009;7(2):132-50.
  11. Executive Committee of the German Medical Association on the recommendation of the Scientific Advisory Board. Cross-sectional guidelines for therapy with blood components and plasma derivatives. 2014.
  12. Killick S, Carter C, Culligan D, Dalley C, Das-Gupta E, Drummond M, et al. Guidelines for the diagnosis and management of adult myelodysplastic syndromes. British Journal of Haematology. 2014;164(4):503-25.
  13. Lieberman L, Sholapur NS, Bercovitz RS, Heddle N, Stanworth S, Arnold DM. Platelet transfusions in critically ill patients with thrombocytopenia: An evidence-based review. Blood. 2013.
  14. Shah A, Stanworth SJ, Doidge JC, Watkinson PJ. Prophylactic platelet transfusions in critical care: How low can you go? J Intensive Care Soc. 2023;25(2):123-127.
  15. Assir MZK, Kamran U, Ahmad HI, Bashir S, Mansoor H, Anees SB, et al. Effectiveness of platelet transfusion in dengue fever: A randomized controlled trial. Transfusion Medicine and Hemotherapy. 2013;40(5):362-8.
  16. Estcourt L, Stanworth S, Doree C, Trivella M, Hopewell S, Blanco P, et al. Different doses of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation (Review). Cochrane Database of Systematic Reviews. 2015;2015(10):CD010984.
  17. Kaufman RM, Assmann SF, Triulzi DJ, Strauss RG, Ness P, Granger S, et al. Transfusion-related adverse events in the Platelet Dose study. Transfusion. 2015;55(1):144-53.
  18. Sato T, Tsuno NH, Goto N, Hagino T, Tasaki T. Incidence and severity of adverse effects related to platelet transfusion: a narrative review of the literature and the recent hemovigilance data of Japan. Ann Blood 2021;6:24.
  19. Kaufman RM, Djulbegovic B, Gernsheimer T, Kleinman S, Tinmouth AT, Capocelli KE, et al. Platelet transfusion: a clinical practice guideline from the AABB. Ann Intern Med. 2015;162(3):205-13.
  20. Estcourt LJ, Stanworth SJ, Doree C, Hopewell S, Trivella M, Murphy M. Comparison of different platelet count thresholds to guide administration of prophylactic platelet transfusion for preventing bleeding in people with haematological disorders after myelosuppressive chemotherapy or stem cell transplantation. Cochrane Database of Systematic Reviews. 2015;2015(11):CD010983.
  21. Lozano M, Mahon A, van der Meer PF, Stanworth S, Cid J, Devine D, et al. Counting platelets at transfusion threshold levels: impact on the decision to transfuse. A BEST Collaborative - UK NEQAS(H) International Exercise. Vox Sanguinis. 2014;106(4):330-6.
  22. Sola-Visner M, Leeman KT, Stanworth SJ. Neonatal platelet transfusions: New evidence and the challenges of translating evidence-based recommendations into clinical practice. J Thromb Haemost. 2022;20(3):556-564.
  23. Curley A, Stanworth SJ, Willoughby K, Fustolo-Gunnink SF, Venkatesh V, Hudson C, et al. Randomized Trial of Platelet-Transfusion Thresholds in Neonates. N Engl J Med. 2019;380(3):242-251.
  24. Chotas W, Wallman-Stokes A, Patel RM, Cooper C, Soll R. Platelet transfusion thresholds for thrombocytopenic infants. Cochrane Database Syst Rev. 2024 Jan 17;2024(1):CD015341. doi: 10.1002/14651858.CD015341. PMCID: PMC10792708.
  25. Kumar A, Mhaskar R, Grossman BJ, Kaufman RM, Tobian AA, Kleinman S, et al. Platelet transfusion: a systematic review of the clinical evidence. Transfusion. 2015;55(5):1116-27.
Relevant Guidelines
  1. National Institute for Health and Care Excellence NICE2015
  2. AABB platelet transfusion guidelines AABB2015
  3. ICTMG platelet guidelines.: Platelets | ICTMG
  4. The National Blood Authority’s Patient Blood Management Guidelines. National Blood uthority Australia (updated 2024). https://www.blood.gov.au/patient-blood-management-guidelines
  5. The Board of the German Medical Association Guidelines Executive Committee of the German Medical Association on the recommendation of the Scientific Advisory Board2014
  6. Schiffer CA, Bohlke K, Delaney M, Hume H, Magdalinski AJ, McCullough JJ, et al. Platelet Transfusion for Patients With Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update. J Clin Oncol. 2018;36(3):283-99. (ASCO 2018)
  7. Estcourt LJ, Birchall J, Allard S, Bassey SJ, Hersey P, Kerr JP, et al. Guidelines for the use of platelet transfusions. Br J Hematol. 2017;176(3):365-94. (BSH 2017)
  8. Liumbruno G, Bennardello F, Lattanzio A, Piccoli P, Rossetti G. Recommendations for the transfusion of plasma and platelets. Blood Transfus. 2009;7(2):132-50. (SIMTI 2009)
  9. Takami A, Matsushita T, Ogata M, Fujii N, Hato T, Tomiyama Y, et al. Guideline for the use of platelet transfusion concentrates based on scientific evidence. Jpn J Transfus Cell Ther. 2017;63(4):569-84. (JSTMCT 2017 in Japanese)
Available training and e-learning resources
  1. Learn Blood Transfusion. NHS2016. Blood Transfusion - elearning for healthcare
  2.  AABB 2016. Education - Association for the Advancement of Blood & Biotherapies
Additional Reading
  1. Transfusion Evidence Library. Transfusion Evidence Library

The authors

The original version was created by Lise Estcourt, the current version was revised by Tomohiko Sato.

Lise Estcourt

Lise Estcourt

Associate Medical Director Research, Development and Quality Improvement for Transfusion, NHS Blood and Transplant, Oxford, UK

Tomohiko Sato

Tomohiko Sato

Associate Professor, Division of Transfusion Medicine and Cell Therapy, The Jikei University Hospital, Tokyo, Japan

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