THROMBOSPONDIN MEASURED IN WHOLE-BLOOD - AN INDICATOR OF PLATELET ACTIVATION

Abnormal platelet activation may be involved in prethrombotic states a nd lend to thromboembolism, When platelets become activated, they rele ase thrombospondin (TSP) from their or-granules which binds mainly to the surface of activated platelets, platelet;derived microparticles an d other blood cells. To determine bound as well as free TSP in a singl e assay, we developed an indirect ELISA to measure TSP in fixed whole blood The intra-assay variance was less than 5% and 97% of purified st andard TSP, added to whole blood samples, was recovered with the ELISA . Blood collected with a 20G needle into a syringe resulted in lower ' whole blood TSP' values than blood collected with the Vacutainer syste m. Whole blood TSP levels were measured in 66 healthy blood donors (20 F, 46M) aged 25-75 years. The mean whole blood TSP concentration was 3 3 +/- 19 ng/ml. No significant difference in whole blood TSP was found between healthy females and males (35 +/- 23 ng/ml vs. 33 +/- 17 ng/m l).