27th May 2023

Platelet transfusion

ABO compatible platelets should be used wherever possible. Platelet transfusion is indicated if:

• An invasive procedure/surgery must be carried out and the platelet count is <50×10⁹/L. If this is for neurosurgery or eye surgery, a platelet count of 100×10⁹/L is used.
• In major haemorrhage, a platelet count of >75×10⁹/L should be maintained or >100×10⁹/L if poly-trauma and concern over head/spinal/eye injuries.
• In DIC where there is bleeding, a platelet count of >50×10⁹/L should be maintained. In non-bleeding patients, transfusion is indicated if the platelet count is <10×10⁹/L. Some centres use a threshold of 20×10⁹/L.
• In reversible bone marrow failure, for example during high intensity chemotherapy, where the platelet count is <10×10⁹/L. In chronic bone marrow failure such as myelodysplastic syndrome (MDS), the use of platelets should be guided by symptoms.

Platelet transfusions should not be administered in cases of peripheral platelet destruction, as in immune thrombocytopenic purpura except in cases of life-threatening bleeds. Treatment should instead focus on immunosuppression to reduce platelet destruction or raising platelet production through thrombopoietin mimetics like Eltrombopag or Romiplostim.

Platelet transfusion is contraindicated in thrombotic thrombocytopenic purpura (TTP) and haemolytic uraemic syndrome (HUS) because it will contribute to further microthrombi.

Platelet refractoriness is defined as a platelet increment <10×10⁹/L at 10-60 minutes occurring after more than 1 transfusion. Reduced increments may be due to consumption in bleeding, DIC or hypersplenism or due to immune destruction due to HLA or human platelet antigen (HPA) antibodies. If HLA or HPA antibodies are detected, matched platelets should be prescribed.