Evaluation of the Anticoagulants EDTA and Citrate, Theophylline, Adenosine, and Dipyridamole (CTAD) for Assessing Platelet Activation on the ADVIA 120 Hematology System

Abstract

Background: Monitoring of platelet activation by the ADVIA® 120 Hematology System requires an anticoagulant and protocol that ensures that platelets are sphered and their activation status is not altered artifactually in vitro. Methods: Blood from healthy controls was collected into tripotassium EDTA; citrate, theophylline, adenosine, and dipyridamole (CTAD); or a combination of both (E/C) and stored at ambient temperature or at 4 °C (E/C only) and then analyzed between 0 and 180 min later on the ADVIA 120. In addition, immunofluorescent flow cytometry was used to identify activated platelets and platelet-leukocyte aggregates. Results: In blood stored with all three anticoagulants, the platelet count changed little, but the mean platelet volume (MPV) at first decreased and then increased, whereas the mean platelet component (MPC; an indicator of activation) changed in a reciprocal manner. The changes in MPV and MPC, which reflect platelet sphering and swelling, were greatest between 30 and 60 min in blood stored at ambient temperature, irrespective of which anticoagulant was used, and between 60 and 180 min when blood anticoagulated with E/C was stored at 4 °C. In all anticoagulants, the percentages of platelets expressing CD62P and of leukocytes in platelet-leukocyte aggregates increased significantly (P <0.01) over 180 min at ambient temperature. Only minimal (<2%) increases occurred when blood with E/C was stored at 4 °C. Conclusions: When determining platelet activation ex vivo on the ADVIA 120, blood should be collected into E/C, stored at 4 °C, and analyzed between 60 and 180 min later; these conditions ensure maximum platelet sphering without concurrent artifactual platelet activation.

Prognostic value of platelet indices as determined by ADVIA 120 in patients suspected of having disseminated intravascular coagulation

“…According to our results, although the large platelet parameter did not exhibit a significant difference between survivors and nonsurvivors, MPV, which represents the presence of large platelets, was found to be elevated in nonsurvivors. Mean platelet component concentration is the mean refractive index of platelets, and represents platelet activation status (Macey et al, 2002), and has been used to monitor platelet activation (Macey et al, 2002;Chapman et al, 2003). In the present study, MPC was not associated with a poorer outcome.…”

“…An increased MPV has been reported in patients suffering from myocardial infarction (Endler et al, 2002), diabetes (Tschoepe et al, 1991), stroke (Greisenegger et al, 2004) and immune thrombocytopenia (Kaito et al, 2005). MPC has been proposed as a platelet activation marker (Macey et al, 2002), and more recently, the utilities of platelet indices were evaluated in hypertension (Nadar et al, 2004) and in those with an aortic aneurysm (Ihara et al, 2005).…”

Mean Platelet Component as an Indicator of Platelet Activation in Foals and Adult Horses

“…23 In dogs, good stability has been reported in MPC in refrigerated (4uC) EDTA samples for up to 48 hours, 35 although studies in human medicine indicate worse stability. 22,24,39,40 Other anticoagulants or anticoagulant combinations are being studied to achieve sphering while avoiding platelet activation, which can occur with EDTA. l, 39,41 In undertaking this study retrospectively, there are factors that escape the control of the investigators and that may introduce some skew in the results.…”

“…22,24,39,40 Other anticoagulants or anticoagulant combinations are being studied to achieve sphering while avoiding platelet activation, which can occur with EDTA. l, 39,41 In undertaking this study retrospectively, there are factors that escape the control of the investigators and that may introduce some skew in the results. In this sense, it may be argued that manipulation of samples may account for some platelet activation.…”

Platelet activation markers in children with congenital heart disease associated with pulmonary arterial hypertension

“…All the patient data and informed consent forms signed by parents were collected. 15,16 Blood analysis for platelet indices was also performed at admission for each subject.…”