Pfa-100 method

Platelet function test: A modern and reliable method for determining platelet function is available with the Platelet Function Analyzer 100 (PFA-100). The principle of this method, which is based on the stimulation of flow conditions with high shear forces in whole blood, similar to an injured arteriolar surface, measures the shutter speed of a membrane.

The measurement of the occlusion time records the hemostasis capacity of the platelets and is an indicator for the adhesion and aggregation ability of the platelets under high shear forces. Using collagen and epinephrine as activators, the efficiency of ASS and ASS-like platelet inhibitors is measured. Furthermore, this cell can be used to detect the subtypes of von Willebrand syndrome. The normal value is < 170 s.
Using collagen and ADP as stimulators, effects of GPIIb/GPIIIa receptor blockers can be tested. If the shutter speed is above 170 s, the blood is again passed over a membrane, this time coated with collagen and ADP. If the time is < 114 s, an ASS-induced change in the platelets can be assumed. If the time is > 114 s, another form of platelet disorder is present.

Buffered sodium citrate blood is passed with a defined suction over a membrane coated with collagen and epinephrine. These platelet activators cause the platelets to adhere and aggregate to the collagen and form a coagulum until the membrane is closed. The time from the beginning of the flow until the membrane is closed is called the closure time.

1. HA Neumann (2014) The coagulation system. ABW-Science Publishing House GmbH Berlin.