what is pdw in blood test

Platelet distribution width (PDW) is a measurement of the variability in platelet size, and is considered a marker of platelet function and activation. PDW reflects how uniform the platelets are in size. A normal PDW indicates platelets that are mostly the same size, while a high PDW means that platelet size varies greatly, which may be associated with vascular (blood vessel) disease or certain cancers. PDW is one of the hematological parameters studied in blood samples, along with platelet count (PLT) and mean platelet volume (MPV) . A high PDW means there is a great variation in size, which may be associated with vascular (blood vessel) disease or certain cancers. Sometimes during the test, platelets stick together and the machine gives a false reading, interpreting it as fewer, larger platelets. In that case, the lab may do a blood smear and directly examine the platelets under a microscope. PDW is a simple, practical, and specific marker of activation of coagulation.