After the light transmission of PRP and PPP is set as 0% and 100% respectively, a platelet agonist (ADP, collagen, epinephrine, arachidonic acid or ristocetin) is added to the PRP from the test subject. When PRP is mixed with the agonist, the platelets start to aggregate and the light transmission of the PRP changes. The change in the light transmission is detected and measured with a wavelength of 660 nm.
The reaction mixture is continuously stirred during the reaction by the magnetic stirrer in the test cuvette and the stirring motor underneath the detection channel.
The maximal aggregation (%) is calculated by the maximal amount of change in the light transmission caused by the platelet aggregation which is induced by the platelet agonist.