Characteristics of main POC devices used to measure platelet functions tests

Test/Device	Manufacturer	Technique	Unit	Remarks
PFA-100	Siemens Diagnostic Deerfield, Illinois	Measures time to complete occlusion an aperture in a capillary-like membrane under sheer force	Closure time (for all 3 assays)	Three assays vary in platelet agonist: CEPI assay, CADP assay, and Innovance. Simulates physiologic conditions, significantly affected von Willebrand factor
Platelet Works	Helena Laboratories Beaumont, Texas	Measures platelet count before and after addition of platelet activating factor	% Aggregation	Time dependent
Impact and Impact-R	DiaMed, Cressier, Switzerland	Measures platelet inhibition induced by shear stress	Surface coverage, average size	Simulates physiologic conditions, significantly affected von Willebrand factor, Impact-R more suitable for testing antiplatelet effect
VerifyNow	Accumetrics, San Diego, California	Measures optical signal of light transmitted through whole blood which depends on the degree of platelet aggregation around fibrinogen coated beads	Aspirin Reaction Units (Aspirin assay), P2Y12 Reaction Units (P2Y12 assay), Platelet Aggregation Units (GP IIb/IIIa assay)	Three assays vary in platelet agonist: Aspirin assay, P2Y12 assay, and Gp IIb/IIIa assay. Based on the same concept of light transmittance as, and correlates well with LTA
			P2Y12 assay: PRUs, GP IIb/IIIa assay: PAUs
Clot Signature Analyzer	Xylum Corporation Scarsdale, New York	Measures the time for platelets to occlude holes “punched” in a blood conduit and collagen-induced thrombus formation as blood flows in a channel containing a collagen fiber	Platelet Hemostasis Time (bleeding time equivalent), Clot Time (ACT equivalent), Collagen Induced Thrombus Formation	Assess multiple aspects of hemostasis under near-physiologic conditions