The IMPACT PGE1 reagent is used in conjunction with ADP to diagnose platelet dysfunction or normal platelet activity in human whole blood.

It is designed to increase the sensitivity of ADP-induced platelet aggregation to the effects of P₂Y₁₂ antagonists (e.g. clopidogrel).

PGE1 is a natural platelet inhibitor that triggers an increase in platelet cAMP levels. A decrease in platelet cAMP levels leads to platelet activation. An increase in platelet cAMP levels counteracts platelet activation. The addition of PGE1 to platelet aggregation tests with ADP results in moderate inhibition of platelet activation in healthy normal blood samples but significantly increases the sensitivity of the ADP test to the inhibition of platelet reactivity by P₂Y₁₂ antagonists (e.g. clopidogrel).