How much does the platelet count increase per unit of platelets transfused?

From the Guidelines

One unit of platelets transfused can be expected to increase the platelet count by 5,000–10,000 platelets per microliter (5-10 × 10^9/L) in an adult patient. This estimate is based on the most recent and highest quality study available, which suggests that platelets pooled from 5 or 6 single donors or derived from apheresis of a single donor can increase the platelet count by this amount when infused 1. The total volume infused is approximately 250 mL of platelet-rich plasma/unit. It's essential to note that the actual increase in platelet count may vary depending on several factors, including patient size, presence of fever, sepsis, splenomegaly, disseminated intravascular coagulation (DIC), or other conditions that increase platelet consumption or sequestration.

Some key points to consider when assessing the effectiveness of platelet transfusions include:

• The underlying cause of thrombocytopenia, with better responses typically seen in patients with decreased production rather than increased destruction or consumption of platelets
• The need to measure platelet count approximately 1 hour post-transfusion and again at 24 hours to assess both immediate response and platelet survival
• The use of a rough estimate of an absolute increment of 2,000/unit of PC or 10,000/transfusion of apheresis platelets to be equivalent to a CCI of 5,000, as suggested by the American Society of Clinical Oncology 1
• The importance of monitoring post-transfusion platelet counts to determine the adequacy of platelet transfusion therapy and to investigate the cause of platelet transfusion refractoriness if necessary 1

From the Research

Platelet Count Increase per Unit of Platelets Transfused

• The increase in platelet count per unit of platelets transfused can vary depending on several factors, including the dose of platelets transfused and the patient's body size 2, 3.
• A study found that the mean posttransfusion platelet count increment was 17,010 per microL for a lower-dose platelet component (LDP) and 31,057 per microL for a higher-dose platelet component (HDP) 2.
• Another study suggested that each 1 x 10(11) platelets transfused will increase the blood platelet count approximately 10 x 10(9)/L per each square meter of patient body surface area 3.
• A retrospective chart review found that 2-unit platelet transfusions resulted in a higher immediate post-transfusion platelet count (43 vs. 37 x 10(3) /μl) compared to 1-unit transfusions, but did not increase the number of days between outpatient transfusions or the platelet count at the time of next transfusion 4.

Factors Affecting Platelet Count Increase

• The patient's body size can affect the increase in platelet count, with larger patients requiring more platelets to achieve the same increase in platelet count 3.
• The dose of platelets transfused can also affect the increase in platelet count, with higher doses resulting in greater increases in platelet count 2, 3.
• Other factors, such as splenomegaly, ABO mismatching, and the use of certain medications, can also affect the response to platelet transfusions 5.

Clinical Implications

• The optimal dose of platelets for transfusion is still being evaluated, but a dose of 3 x 10(11) platelets is often considered adequate for adult patients 3.
• Prophylactic platelet transfusions are often given at a trigger of 10,000/microL, while therapeutic transfusions may require higher triggers 5.
• Leukoreduction can reduce the risk of platelet alloimmunization and other complications, but its effect on immunomodulatory effects is still controversial 5.