What are the indications for platelet (platelets) transfusion?

Platelet Transfusion Indications

Platelet transfusions are indicated prophylactically at specific count thresholds based on clinical context, and therapeutically for active bleeding with thrombocytopenia or platelet dysfunction.

Prophylactic Transfusion Thresholds (No Active Bleeding)

Hypoproliferative Thrombocytopenia

• Transfuse at platelet count <10 × 10⁹/L for patients with therapy-induced hypoproliferative thrombocytopenia (chemotherapy or allogeneic stem cell transplant) 1, 2
• This threshold is supported by strong evidence showing no increase in mortality or bleeding compared to higher thresholds 2
• Do NOT transfuse prophylactically in adults with aplastic anemia or undergoing autologous stem cell transplant unless bleeding occurs 2

Consumptive Thrombocytopenia

• Transfuse at platelet count <25 × 10⁹/L for neonates without major bleeding 2
• Transfuse at platelet count <10 × 10⁹/L for adults with consumptive thrombocytopenia without major bleeding 2
• Do NOT transfuse in dengue patients with consumptive thrombocytopenia without major bleeding, as it does not reduce clinical bleeding and increases adverse events 3, 2

Procedural Thresholds

Low-Risk Procedures

• Central venous catheter (CVC) insertion in compressible sites: <10 × 10⁹/L 2
  • The 2025 AABB guidelines represent a shift from older recommendations of 20 × 10⁹/L 1
  • However, the 2025 Association of Anaesthetists maintains a threshold of 20 × 10⁹/L 1
  • Clinical caveat: Avoid subclavian CVCs in severely thrombocytopenic patients with hematological conditions 1

Moderate-Risk Procedures

• Lumbar puncture: <20 × 10⁹/L 2

  • This represents updated guidance from the 2025 AABB guidelines, lower than the previous 50 × 10⁹/L threshold 1
  • The 2025 Association of Anaesthetists recommends 40 × 10⁹/L 1
  • Use clinical judgment for counts 20-50 × 10⁹/L in adults, as most data supporting lower thresholds come from pediatric studies 1

• Interventional radiology low-risk procedures: <20 × 10⁹/L 2

• Percutaneous tracheostomy: <50 × 10⁹/L 1

• Percutaneous liver biopsy: <50 × 10⁹/L (consider transjugular approach if below this) 1

High-Risk Procedures

• Major nonneuraxial surgery: <50 × 10⁹/L 1, 2
• Interventional radiology high-risk procedures: <50 × 10⁹/L 2
• Epidural catheter insertion/removal: <80 × 10⁹/L 1
• Neurosurgery or posterior segment ophthalmic surgery: <100 × 10⁹/L 1

Therapeutic Transfusion (Active Bleeding)

General Bleeding

• Maintain platelet count >50 × 10⁹/L for patients with active significant bleeding 1, 3
• Transfusion may be indicated despite adequate platelet counts if platelet dysfunction is known or suspected (uremia, cardiopulmonary bypass, antiplatelet drugs) 4

Severe Bleeding Contexts

• Maintain platelet count >100 × 10⁹/L for multiple traumatic injuries, traumatic brain injury, or spontaneous intracerebral hemorrhage 1
• Do NOT transfuse for nonoperative intracranial hemorrhage in adults with platelet count >100 × 10⁹/L, even if receiving antiplatelet agents 2

Cardiovascular Surgery

• Do NOT transfuse routinely for patients without thrombocytopenia undergoing cardiopulmonary bypass in the absence of major hemorrhage 2
• Transfusion is appropriate for perioperative bleeding with thrombocytopenia or suspected platelet dysfunction 1

Dosing Considerations

• Standard dose: 3-4 × 10¹¹ platelets (one apheresis unit or 4-6 pooled concentrates) 5, 4
• Higher doses (0.07 × 10¹¹/kg) extend transfusion intervals from 2.6 to 4.1 days but do not improve recovery percentage 6
• Verify post-transfusion count to confirm desired platelet level achieved 3

Critical Pitfalls to Avoid

• Do not apply cancer prophylaxis thresholds (10 × 10⁹/L) to dengue, where thrombocytopenia results from destruction rather than hypoproliferation 3
• Consider additional bleeding risk factors (sepsis, fever >38°C, active bleeding, recent trauma/surgery, anticoagulant use, peptic ulcer disease, hypertension, advanced age) that may warrant transfusion at higher thresholds 1, 3, 7
• Verify extremely low counts with manual review, as automated counters may be inaccurate 5
• Consider HLA-compatible platelets for alloimmunized patients with poor increments 5