Currently available methods for platelet function analysis: advantages and disadvantages

Platelets play a pivotal role in normal hemostasis, and derangement of their function can lead to hemorrhage or thrombosis. While progress has been made in elucidating the molecular mechanisms leading to platelet adhesion, aggregation, shape change and secretion, clinically useful tests of platelet function have lagged. A number of dedicated platelet function instruments that are much simpler to use and are now utilized as point-of-care (POC) instruments have now become available. Some instruments have been incorporated into routine clinical use and can be utilized not only as general screening tests of platelet function but as monitors of antiplatelet therapy and to potentially assess both risk of bleeding and/or thrombosis. Some of the factors that differentiate these tests are sample volume requirements, the use of whole blood, the presence of shear, POC status, need for a technician and expense. The following is a review of some of the commonly used tests of platelet function, along with their advantages and disadvantages. The tests and pertinent instruments described are based on aggregation, shear stress platelet contribution to clot strength, flow cytometry and serum and urinary thromboxane metabolites.