Phenotypic biomarkers
| Assays . | Sample . | Principle of assay . | Measurement method . | Analytical validity† (range) . | Biological validity . | Clinical validity . | Clinical utility . |
|---|---|---|---|---|---|---|---|
| LTA | Platelet-rich plasma | ADP-induced platelet aggregation | Light absorbance | CV = 3.3-11.3% | † | Low-quality evidence | ‡ |
| VerifyNow P2Y12 | Whole blood | ADP-induced platelet aggregation (with PGE1 modulation) | Light absorbance | CV = 6-7.5%, r = 0.35-0.86 | † | Moderate-quality evidence | ‡ |
| k = 0.2-0.82 | |||||||
| Multiplate electrode aggregometry (MEA) | Whole blood | ADP-induced platelet aggregation | Electrical impedance | CV = 5-10% | † | Low-quality evidence | ‡ |
| r = 0.25-0.87 | |||||||
| k = 0.1-0.7 | |||||||
| PFA-100 (INNOVANCE P2Y) | Whole blood | Shear-dependent ADP-induced platelet adhesion and aggregation | Closure time: Time for platelet plug to stop blood flow across aperture | CV = 7.7-9.5% | † | Low-quality evidence | ‡ |
| r = −0.7 to −0.11 | |||||||
| k = 0.14-0.35 | |||||||
| Thromboelastography (Haemoscope TEG) | Whole blood | Kinetic changes with ADP- induced clot formation | Tensile strength of clot | CV = 4.5-6.6% | † | Insufficient evidence | ‡ |
| r = 0.32-0.82 | |||||||
| k = −0.02 to 0.81 | |||||||
| Vasodilator stimulatory protein assay (VASP) | Whole blood | ADP-induced P2Y12 receptor activation–dependent phosphorylation | Flow cytometry to quantify VASP phosphorylation | CV = 2.3-6.6% | † | Low-quality evidence | ‡ |
| r = 0.36-0.72 | |||||||
| k = −0.04-0.31 |
| Assays . | Sample . | Principle of assay . | Measurement method . | Analytical validity† (range) . | Biological validity . | Clinical validity . | Clinical utility . |
|---|---|---|---|---|---|---|---|
| LTA | Platelet-rich plasma | ADP-induced platelet aggregation | Light absorbance | CV = 3.3-11.3% | † | Low-quality evidence | ‡ |
| VerifyNow P2Y12 | Whole blood | ADP-induced platelet aggregation (with PGE1 modulation) | Light absorbance | CV = 6-7.5%, r = 0.35-0.86 | † | Moderate-quality evidence | ‡ |
| k = 0.2-0.82 | |||||||
| Multiplate electrode aggregometry (MEA) | Whole blood | ADP-induced platelet aggregation | Electrical impedance | CV = 5-10% | † | Low-quality evidence | ‡ |
| r = 0.25-0.87 | |||||||
| k = 0.1-0.7 | |||||||
| PFA-100 (INNOVANCE P2Y) | Whole blood | Shear-dependent ADP-induced platelet adhesion and aggregation | Closure time: Time for platelet plug to stop blood flow across aperture | CV = 7.7-9.5% | † | Low-quality evidence | ‡ |
| r = −0.7 to −0.11 | |||||||
| k = 0.14-0.35 | |||||||
| Thromboelastography (Haemoscope TEG) | Whole blood | Kinetic changes with ADP- induced clot formation | Tensile strength of clot | CV = 4.5-6.6% | † | Insufficient evidence | ‡ |
| r = 0.32-0.82 | |||||||
| k = −0.02 to 0.81 | |||||||
| Vasodilator stimulatory protein assay (VASP) | Whole blood | ADP-induced P2Y12 receptor activation–dependent phosphorylation | Flow cytometry to quantify VASP phosphorylation | CV = 2.3-6.6% | † | Low-quality evidence | ‡ |
| r = 0.36-0.72 | |||||||
| k = −0.04-0.31 |
k, κ statistics; PGE1, prostaglandin E1; r, correlation coefficient.
CV refers to intra-assay coefficient of variation; measures of test agreement (k) and correlation (r) refer to the comparison of given test with LTA.
All measure consequences of ADP-induced platelet activation.
Insufficient evidence to prove or disprove clinical utility of a biomarker strategy.