Assessment of platelet function: Laboratory and point-of-care methods

Table 1 Laboratory and point-of-care assays for evaluation of platelet function

Platelet function tests	Principle of method	Application of the methods
Platelet adhesion studies
Bleeding time	In vivo stopping of blood flow	Screening test of platelet function on defects of primary hemostasis
Platelet Function Analyzer - PFA-100/InnovancePFA-200	In vitro stopping of high shear blood flow by platelet plug in whole blood	Assessment of bleeding risk, thrombotic risk, drug effects Sensitive to severe platelet dysfunctions Detection of VWD
Impact Cone and Plate(let) analyzer	Shear-induced platelet adhesion/aggregation onto surface in whole blood	Screening of congenital primary hemostasis abnormalities Evaluation of platelet response to aspirin and clopidogrel (scarce data).
Platelet-To-Platelet Aggregation Studies
Light transmission platelet aggregation	Low shear platelet-to-platelet aggregation in response to agonists in platelet-rich-plasma	Screening test for bleeding behavior Diagnostic for platelet surface glycoprotein defects Monitoring of the platelet response to antiplatelet agents
Impedance platelet aggregation	Low shear platelet-to-platelet aggregation in response to agonists in whole blood	Screening test for bleeding behavior Diagnostic for platelet surface glycoprotein defects Monitoring of the platelet response to antiplatelet agents
VerifyNow system	Fibrinogen-platelet agglutination in response to agonist in whole blood	Monitoring of the platelet response to antiplatelet agents
Plateletworks	Platelet counting pre- and post-activation in whole blood	Monitoring of the platelet response to antiplatelet agents
Analysis of Clot Formation
Thromboelastography/ Thromboelastometry	Monitoring of rate and quality of clot formation in whole blood based on viscoelastic blood changes	Assessment of global haemostasis Possible definition of different platelet and clotting abnormalities Diagnosis and treatment of bleeding after cardiac surgery, liver transplantation, trauma and PPH
Platelet function tests to investigate platelet activation
Flow cytometry	Cell counting, cell sorting, biomarker detection and protein engineering laser-based detection of suspending fluorescent label platelets in a stream of fluid	Expression of platelet specific surface and/or cytoplasmatic markers; VASP phosphorylation state1 (Monitoring of CD41/61, CD42, CD62P, etc. Activation markers directly dependent on thienopyridine target)
Radio- or Enzyme Linked-Immune Assays: Soluble markers determination1	Ligand binding assays	Measurement of Beta-thromboglobulin, PF4, GPV, Soluble P-Selectin, Thromboxanes

¹Not planned in this report. GP: Glycoprotein; PPH: Post-partum hemorrhage; VASP: Vasodilator-stimulated phosphoprotein; VWD: Von Willebrand Disease.