From the Guidelines
Administering 2 units of platelet concentrate to a patient with a platelet count of 59,000/μL will typically increase the platelet count by approximately 30,000-60,000/μL, as each unit of platelet concentrate generally raises the platelet count by 15,000-30,000/μL in an average-sized adult with no ongoing consumption or destruction of platelets, as suggested by the most recent study 1.
Expected Platelet Count Increase
The expected increase in platelet count can vary based on several factors, including:
- Patient's body surface area
- Presence of splenomegaly
- Ongoing platelet consumption (such as in DIC or ITP)
- Fever
- Sepsis
- Bleeding It is essential to check a post-transfusion platelet count to assess the actual response, typically measured 1 hour after transfusion completion, as recommended by 1.
Platelet Transfusion Guidelines
The American Society of Clinical Oncology clinical practice guideline update 1 suggests that patients remain at risk of hemorrhagic events if the post-transfusion counts are still at or below the platelet value used to trigger the initial transfusion. Therefore, monitoring the post-transfusion count allows the practitioner to determine the adequacy of platelet transfusion therapy.
Important Considerations
If the increment is less than expected, platelet refractoriness should be considered, which may require HLA-matched platelets for subsequent transfusions, as noted in 1. Additionally, platelets have a short shelf life and should be transfused promptly when received from the blood bank.
Calculation of Platelet Increment
The platelet increment can be calculated using the formula: absolute increment × body-surface area (m2)/number of platelets transfused × 1011, as described in 1. Alternatively, a rough estimate of an absolute increment of 2,000/unit of PC or 10,000/transfusion of apheresis platelets can be used, as suggested by 1.
From the Research
Platelet Count Increase After Transfusion
- The expected increase in platelet count after receiving 2 units of platelet concentrate can be estimated based on the dose of platelets transfused and the patient's body surface area 2.
- According to the study by 2, 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.
- Assuming a standard dose of 3 x 10(11) platelets per unit of platelet concentrate, 2 units would contain approximately 6 x 10(11) platelets.
- For a patient with a body surface area of 1.7-2.0 m2 (average adult), the expected increase in platelet count would be approximately 60-80 x 10(9)/L (10 x 10(9)/L per square meter x 6 x 10(11) platelets).
- However, the actual increase in platelet count may vary depending on factors such as the patient's condition, the presence of bleeding or splenomegaly, and the quality of the platelet transfusion 3, 2.
- A study by 3 reported a median platelet count increase of 14 x 10(9)/L (interquartile range, -2 to 30) after a single platelet transfusion, but this increase may not be directly applicable to the patient in question due to differences in patient population and transfusion protocols.
Patient-Specific Factors
- The patient's initial platelet count is 59 x 10(9)/L, which is below the normal range but not severely thrombocytopenic.
- The patient's body surface area and weight are not provided, which could affect the estimated increase in platelet count.
- The presence of any underlying medical conditions, such as bleeding or splenomegaly, could also impact the effectiveness of the platelet transfusion 3, 2.