Murine whole blood was obtained (with ACD anticoagulented) by heart puncture, then PRP (platelet rich plasma) and PPP were prepared by centrifugantion. We failed to induce Murine platelets aggregation by AA\ADP\Collagen (3 agonists were added separately or together ) in platelet function test (LTA, Helena), the max aggregation rate was 17% at present. To test the effective of agonists, we repeated platelet function test（PFT） with human samples, and got normal results.

So, is there any key steps in PRP preparation we ignored? Diluting PRP sample with PBS favors in test?

Thank you for your kindness and your time to read and reply.