Platelet transfusion

Platelet transfusion, also known as platelet concentrate, is used to prevent or treat bleeding in people with either a low platelet count or poor platelet function. Often this occurs in people receiving cancer chemotherapy. Preventative transfusion is often done in those with platelet levels of less than 10 x 109/L. In those who are bleeding transfusion is usually carried out at less than 50 x 109/L. Blood group matching (ABO, RhD) is typically recommended before platelets are given. Unmatched platelets, however, are often used due to the unavailability of matched platelets. They are given by injection into a vein. Platelet transfusion, also known as platelet concentrate, is used to prevent or treat bleeding in people with either a low platelet count or poor platelet function. Often this occurs in people receiving cancer chemotherapy. Preventative transfusion is often done in those with platelet levels of less than 10 x 109/L. In those who are bleeding transfusion is usually carried out at less than 50 x 109/L. Blood group matching (ABO, RhD) is typically recommended before platelets are given. Unmatched platelets, however, are often used due to the unavailability of matched platelets. They are given by injection into a vein. Side effects can include allergic reactions such as anaphylaxis, infection, and lung injury. Bacterial infections are relatively more common with platelets as they are stored at warmer temperatures. Platelets can be produced either from whole blood or by apheresis. They keep for up to five to seven days. Platelet transfusions came into medical use in the 1950s and 1960s. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. In the United Kingdom it costs the NHS about 200 pounds per unit. Some versions of platelets have had the white blood cells partially removed or been gamma irradiated which have specific benefits for certain populations. 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 less than 10 x 109/L. If the person is well using a higher platelet count threshold does not reduce the risk of bleeding further. A review in people with blood cancers receiving intensive chemotherapy or a stem cell transplant found that overall giving platelet transfusions when the platelet count is less than 10 x 109/L reduced the number of bleeding events and days with significant bleeding. However, this benefit was only seen in certain patient groups, and people undergoing an autologous stem cell transplant derived no obvious benefit. Despite prophylactic platelet transfusions, people with blood cancers often bleed, and other risk factors for bleeding such as inflammation and duration of thrombocytopenia should be considered. There is little evidence for the use of preventative platelet transfusions in people with chronic bone marrow failure, such as myelodysplasia or aplastic anemia. Multiple guidelines recommend prophylactic platelet transfusions are not used routinely in people with chronic bone marrow failure, and instead an individualised approach should be taken. Several studies have now assessed the benefit of using preventative platelet transfusions in adults with dengue who have profound thrombocytopenia (platelet count < 20 x 109/L. There is no evidence that this reduce the risk of bleeding, but there is evidence that they increase the risk of harm due to the platelet transfusion (increased risk of a transfusion reaction including anaphylaxis). A review in people with blood cancers receiving intensive chemotherapy or a stem cell transplant found that overall giving platelet transfusions when the platelet count is less than 10 x 109/L compared to giving platelet transfusions when the platelet count is less than 20 or 30 x 109/L had no effect on the risk of bleeding. Higher platelet transfusion thresholds have been used in premature neonates, but this has been based on limited evidence. There is now evidence that using a high platelet count threshold (50 x 109/L) increases the risk of death or bleeding compared to a lower platelet count threshold (25 x 109/L) in premature neonates.