Table 2.

Overview of published clinical microparticle studies.

Performance topic	Reference	Type of microparticle assay	Total number of subjects in study	Concentration [MP/L]	Summary statement
Accurate enumeration of microparticles (especially in the presence of platelets or other particles)	Balvers et al. 2015 [51]	FC	20 (10 trauma patients; 10 healthy)	7.5 × 103	Flow cytometry does not count microparticles if bound in complexes; reported concentration is about 106 lower than reported elsewhere; sample was prepared at low temperature
	Jayachandran et al. 2011 [52]	FC	118 (58 assayed for plasma microparticles)	N/A	Flow cytometry does not detect aggregates
	van Ierssel et al. 2012 [53]	FC	13 in vitro lipid (5 coronary heart disease; 8 healthy); 5 in vivo lipid, healthy	2.5 × 108 (EMP only)	Flow cytometry data are affected by high circulating levels of lipids
Size of microparticles (below the detection limit of many technologies)	Leong et al. 2011 [55]	FC	6 (acute myocardial infarction; healthy)	3 × 109	Platelet microparticle size is below stated detection limits of most flow cytometers. However, study confirmed that flow cytometry is capable of analyzing microparticles from plasma; approximately 2-fold for acute myocardial infarction (AMI) patient
	Robert et al. 2012 [56]	FC	40 (30 coronary disease; 10 healthy)	2.0 × 109 (1.1 × 1010 with high sensitivity FCM)	Standard flow cytometry does not detect small microparticles. High-sensitivity flow cytometry allows measurement of previously undetectable microparticles; approximately 10-fold for coronary patients
Probe/marker selection	Hou et al. 2011 [77]	FC	20 healthy donors	1 × 109 (fresh)  1.5 × 1010 (day 9)	Annexin V does not bind to membranes at low phosphatidyl-serine levels and is Ca2+ dependent; lactadherin is proposed as an alternative
	Iversen et al. 2013 [58]	FC	49 (20 healthy; 29 systemic lupus erythematosus)	9 × 109	Annexin V binding is Ca2+ dependent, resulting in potential clotting of plasma; approximately 2-fold for patients with systemic lupus erythematosus (SLE)
	Lanuti et al. 2012 [78]	FC	34 (20 diabetes; 14 healthy)	1.1 × 108 (EMP only)	Endothelial microparticles and circulating endothelial cells share markers such as CD144 and CD146 leading to overestimation; approximately 2-fold for patients with type 2 diabetes (Iversen et al. published endothelial microparticle concentration to be a factor 10 lower than platelet microparticles)
	Bohling et al. 2012 [45]	ELISA, clot-based and chromogenic and flow cytometry	75 (24 healthy, 28 trauma, 23 nontrauma (patients taking warfarin, heparin, or lupus anticoagulants))	4 × 1010	The performance characteristics of a clot-based versus chromogenic procoagulant phospholipid assay were compared and low correlation found; neither assay was considered optimal
Standardization of methods	Marchetti et al. 2014 [61]	ELISA, clot-based and thrombin generation	145 (72 control, 73 essential thrombocythemia)		The performance characteristics of clot-based procoagulant phospholipid assay and thrombin generation assay were compared
Method selection	Strasser et al. 2013 [62]	FC, prothrombinase ELISA, clot-based ELISA	31 healthy donors	1.2 × 109	The performance characteristics of a clot-based procoagulant phospholipid assay, prothrombinase assay, and flow cytometry were compared
	Labrie et al. 2013 [20]	DLS	24 apheresis platelet concentrates from normal volunteers	1.5 × 1012	ThromboLUX microparticle assay was compared to flow cytometry and correlated highly
	Xu et al. 2011 [44]	DLS	160 (81 platelet-rich plasma, 79 apheresis platelet concentrates)	2 × 1011	ThromboLUX microparticle assay was compared to flow cytometry [51]; values were calculated from reported relative content but concentrations are not published

Flow cytometry (FC) and dynamic light scattering (DLS).