When do you transfuse platelets?

Platelet Transfusion Thresholds and Indications

For stable patients with hypoproliferative thrombocytopenia (chemotherapy, leukemia, allogeneic stem cell transplant), transfuse prophylactically at platelet counts <10,000/μL; for active significant bleeding, transfuse to achieve ≥50,000/μL regardless of cause. 1, 2

Prophylactic Transfusion in Non-Bleeding Patients

Hypoproliferative Thrombocytopenia (Chemotherapy/Leukemia)

• Transfuse at <10,000/μL in stable patients without bleeding 3, 1, 2
• This threshold reduces platelet consumption by 21.5% compared to 20,000/μL without increasing serious bleeding or mortality 3
• The 10,000/μL threshold is supported by high-quality evidence showing clinically significant hemorrhages occurred in only 3.1% vs 2% of days compared to 20,000/μL threshold 3

Special Populations Where Prophylactic Transfusion is NOT Recommended

• Autologous stem cell transplant patients: Do not transfuse prophylactically 1, 2
• Aplastic anemia with chronic stable thrombocytopenia: Do not transfuse prophylactically 1, 2
• These patients should receive therapeutic (not prophylactic) transfusions only when bleeding is observed 4

Consumptive Thrombocytopenia

• Neonates without major bleeding: Transfuse at <25,000/μL 2
• Adults with sepsis and no bleeding/procedures: Transfuse at <10,000/μL 5
• Adults with sepsis and significant bleeding risk: Transfuse at <20,000/μL 5
• Dengue fever without major bleeding: Do NOT transfuse (strong recommendation) 2

Therapeutic Transfusion for Active Bleeding

• Target platelet count ≥50,000/μL for any patient with active significant bleeding, regardless of underlying cause 3, 1, 2
• This applies to surgical bleeding, obstetric bleeding, and medical bleeding 3
• Transfuse even with apparently adequate counts if platelet dysfunction is suspected (e.g., clopidogrel, uremia, cardiopulmonary bypass) 3, 1

Procedure-Based Thresholds

Low-Risk Procedures

• Central venous catheter at compressible sites: Transfuse at <10,000/μL 1, 2
• This represents an update from previous 20,000/μL recommendations based on accumulating safety data 1

Moderate-Risk Procedures

• Lumbar puncture: Transfuse at <20,000/μL 1, 2
• Large pediatric series showed no significant complications at counts <25,000/μL 1
• Interventional radiology (low-risk): Transfuse at <20,000/μL 2
• Liver biopsy: Transfuse at <50,000/μL 1

High-Risk Procedures

• Major nonneuraxial surgery: Transfuse at <50,000/μL 3, 1, 2
• Interventional radiology (high-risk): Transfuse at <50,000/μL 2
• Vaginal deliveries or procedures with limited blood loss may be performed safely at counts <50,000/μL 3

Neuraxial Procedures

• The determination for platelet counts between 50,000-100,000/μL should be based on potential platelet dysfunction, anticipated bleeding, and risk of bleeding into confined spaces (brain or eye) 3

Special Clinical Situations

Conditions Where Transfusion is Contraindicated or Ineffective

• Thrombotic thrombocytopenic purpura (TTP): Relatively contraindicated due to risk of precipitating thromboses 1
• Idiopathic thrombocytopenic purpura (ITP): Ineffective and rarely indicated except for life-threatening bleeding 3, 1
• Heparin-induced thrombocytopenia (HIT): Ineffective due to increased platelet destruction 3

Cardiac Surgery with Cardiopulmonary Bypass

• Do NOT transfuse routinely in nonthrombocytopenic patients 1, 2
• Transfuse only for perioperative bleeding with documented thrombocytopenia and/or platelet dysfunction 1, 2

Intracranial Hemorrhage

• Do NOT transfuse in adults with platelet count >100,000/μL, including those on antiplatelet agents 2

Dosing and Monitoring

• Standard dose: 4-6 units of pooled platelet concentrates OR 1 apheresis unit 3, 1
• Always obtain post-transfusion platelet count to confirm adequate increment 1
• Typical interval between prophylactic transfusions is every 2-4 days in acute leukemia patients 3
• Larger doses may be needed for bleeding patients or those requiring invasive procedures 3

Critical Pitfalls to Avoid

• Do not rely solely on platelet count: Consider fever >38°C, fresh hemorrhage, coagulopathy, and clinical bleeding signs when deciding to transfuse at counts >10,000/μL 3, 1
• Do not transfuse in conditions with increased platelet destruction (ITP, TTP, HIT, dengue) unless life-threatening bleeding occurs 3, 1, 2
• Do not use FFP to correct laboratory abnormalities in absence of bleeding or planned procedures 5
• Consider platelet dysfunction: Transfusion may be indicated despite adequate counts if dysfunction is known or suspected (antiplatelet drugs, uremia, cardiopulmonary bypass) 3, 1
• Account for measurement variability: Small variations can result from technology limitations; base decisions on clinical situation and pattern of recent counts, not just a single value 3