Investigation - Post-Transfusion Purpura (PTP)

Transfusion services should have clear policies describing the required investigation for transfusion complications.

In Post-Transfusion Purpura (PTP) laboratory tests usually reveal:

• Severe thrombocytopenia
• Normal red cell morphology
• Antibody with specificity for HPA-1a (or other platelet-specific antibody)
• HPA-1a negative phenotype or platelet genotype of HPA-1b/1b (or antigen-negative phenotype/genotype for another platelet specific antigen)

Clinically, PTP needs to be differentiated from Immune Thrombocytopenia Purpura (ITP), Thrombotic Thrombocytopenic Purpura (TTP), drug-induced thrombocytopenia, bacterial sepsis, Disseminated Intravascular Coagulation (DIC), and bone marrow failure. It should also be differentiated from otherwise uncomplicated alloimmunization to platelet specific antigens (See Further Reading- Popoksky MA).