Refractory Platelet Transfusions

Platelet Transfusion Refractoriness

• Usually defined as a response of < 10k in platelets after a transfusion of an apheresis unit in an average sized adult.  A normal increase in platelet count is generally about 30 k.

Etiologies (this is not an exhaustive list):
A.   Non-Immune Causes – account for approximately 2/3rd of cases.

• Sepsis – multiple mechanisms including platelet consumption and sequestration, decreased production by bone marrow, and sometimes concomitant DIC.
• Splenomegaly – transfused platelets get sequestered in the spleen.
• Bleeding – although this is confusing since bleeding is commonly a result of platelet transfusion refractoriness. 
• DIC – due to platelet destruction

B.  Immune Causes – mainly Alloimmunization.

• Diagnosis – a platelet count check 10 minutes to 1 hour after transfusion, along with one ~24 hours after transfusion, is extremely help.
• A normal rise in platelets after 1 hour, but a return to baseline count within 24 hours, is typical of most  non-immune causes of platelet transfusion refractoriness (i.e. sepsis, splenomegaly).  If this is the case, then the appropriate move is to treat the underlying cause.
• If the 1 hour platelet count shows little to no increase, this is more typical of alloimmunization.  Once this is recognized, the primary team should work with the blood bank to HLA-matched platelets to maximize the yield of transfusions.

(Chanu Rhee MD, 5/10/11)