Preanalytical treatment of EDTA-anticoagulated blood to ensure stabilization of the mean platelet volume and component measured with the ADVIA counters.

The mean platelet component (MPC) parameter calculated by the ADVIA blood cell analyzers provides direct information on density, or granularity, of platelets and could become a useful biomarker to detect in vivo platelet activation. Unfortunately, it is largely affected by time and storage conditions in standard anticoagulants based on EDTA. The present study was designed to improve the stability of the MPC in blood specimens to facilitate a more standardized use in different laboratories. Blood from healthy controls was collected into EDTA plus additives, and stored at different conditions. MPC and the mean platelet volume (MPV) were assessed at 30 min and at 1, 3, 6 and 24hours after blood drawing on the ADVIA 2120 system. Flow cytometry was used to evaluate platelet-activation proteins. Ultrastructural morphology of platelets was assessed using electron microscopy. Storage in EDTA increased MPV, decreased MPC, reduced the number of alpha-granules, and induced changes in the phosphorylation patterns of platelet proteins. A solution based on EDTA containing wortmanin and tyrphostin (ED-WORTY), both inhibitors of signaling pathways, provided good stability for most of the parameters tested up to 6 hours at room temperature. Storage at lower temperatures produced more favorable results. ED-WORTY solutions preserved adequate morphology and had minimal influence on other parameters provided by the ADVIA 2120 system. Thus, the additives included in ED-WORTY may be useful for maintaining the stability of MPC for prolonged periods and to facilitate the transport and exchange of samples among institutions and laboratories.