Platelet function tests: a comparative review

Figures & data

Table 1 Different methodologies for assessment of platelet function

Method	Sample	Method application	Method principle
Bleeding time	Native WB	Screening test (obsolete)	In vivo measurement of bleeding block
Tests based on platelet aggregation
Light transmission platelet aggregation (LTA)	Citrated PRP	Screening test for bleeding tendency Diagnostic for platelet defects Monitoring antiplatelet treatment effect	Photo-optical measurement of light transmission increase in relation to agonist-induced platelet aggregation
Impedance platelet aggregation	Citrated WB	Screening test for bleeding tendency Diagnostic for platelet defects Monitoring antiplatelet treatment effect	Measurement of electrical impedance increase in relation to agonist-induced platelet aggregation
Lumiaggregometry	Citrated WB	Detection of storage/release disorders	LTA or WB aggregometry combined with luminescence
Plateletworks	Citrated WB	Monitoring of the platelet response to antiplatelet agents	Platelet counting pre- and postactivation in whole blood
Tests based on platelet adhesion under shear stress
PFA-100; Innovance PFA-200	Citrated WB	Assessment of bleeding risk and drug effects Searching severe platelet dysfunctions, revealing of VWD	Time evaluation of high shear WB flow blocked by platelet plug into a hole in activated surface
Impact; Cone and Plate(let) Analyzer	Citrated WB	Screening of primary hemostasis	Shear-induced platelet adhesion–aggregation upon specific surface
Global thrombosis test (GTT)	Native WB	Evaluation of platelet function and thrombolysis	Measurement of time cessation of WB flow by high shear-dependent platelet plug formation
Platelet function methods combined with viscoelastic test
TEG/platelet mapping system	Citrated WB	Assessment of global hemostasis plus monitoring antiplatelet treatments effect	Evaluation of rate of clot formation based on low shear-induced and agonist addition
ROTEM platelet	Citrated WB	Assessment of global hemostasis plus diagnostic of platelet defects plus monitoring antiplatelet treatments effect	Measurement of electrical impedance increase in relation to agonist-induced platelet aggregation
Platelet analysis based on flow cytometry
Flow cytometry	Citrated WB, PRP, W-Plt	Cell counting, detection platelet activation by extent of expression of surface and/or cytoplasmic biomarkers	Engineering laser-based detection of suspending fluorescent label platelets in a flowing solution
Evaluation of Thromboxane metabolites
Radio- or enzyme-linked immune assays	Serum, urine, citrated Pls	Measurement of TxA2 metabolites (and Beta-TG, PF4, soluble P-selectine)a	Ligand-binding assays

Note:

a Not planned in this review.

Abbreviations: Beta-TG, beta-thromboglobulin; Pls, plasma; PRP, platelet-rich-plasma; ROTEM, rotational thromboelastometry; TEG, thromboelastography; TxA2, thromboxane A2; WB, whole blood; W-Plt, washed platelets; VWD, Von Willebrand disease.

Table 2 Pros and Cons of reviewed platelet function tests

Method	Pro	Contra
Bleeding time	In vivo test, quick No WB processing	Invasive Poorly standardized Dependent on many variables (skin thickness, and temperature operator’s skills)
Light transmission platelet aggregation (LTA)	Historical gold standard Diagnostic method Flexible Different platelet pathways investigated Sensitive to anti-plt therapy	Manual sample processing Pre- and analytic variables High sample volume Time-consuming
Impedance Platelet Aggregometry	No sample processing Diagnostic method Flexible Different platelet pathways investigated Sensitive to anti-plt therapy Close to POCT (multiple system)	Limited HCT and platelet count range
VerifyNow system	Waived POCT No WB processing Easy, quick	Nonflexible Very expensive Monitoring antiplatelet therapy Limited HCT and platelet count
Plateletworks	POC system Minimal sample preparation Easy, rapid screening test	Indirect assay Required adjunctive platelet count Scarce data
PFA-100; Innovance PFA-200	In vitro standardized BT Easy, quick POCT Sensitive to severe platelet defects	Rigid closed system Platelet count – HCT-dependent Not sensitive to platelet secretion defects.
Impact Cone and Plate(let) Analyzer	WB assay Global platelet method Small sample volume	Expensive Experienced staff Lack of clinical studies Not widely available
Global thrombosis test (GTT)	WB assay Global platelet method Small sample volume	Lack of clinical studies Not widely available
TEG platelet mapping	POCT Global hemostasis test Reduces blood transfusions	Measure clot properties More studies are needed
ROTEM platelet	POCT Predicts bleeding Reduces blood transfusions Improves clinical outcome Global hemostasis test WB platelet aggregometry	Limited HCT and platelet count range (for platelet system) Lack of clinical studies

Abbreviations: BT, bleeding time; HCT, hematocrit; plt, platelet; POC, point-of-care; POCT, point-of-care testing; ROTEM, rotational throm boelastometry; TEG, thromboelastography; WB, whole blood.

Figure 1 Light transmission platelet aggregation tracings from a healthy subject in response to different agonists.

Note: (A–F) Final concentrations are reported.
Abbreviation: ADP, adenosine-diphosphate.