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 |