Abstract
Platalet aggregation by ADP was measured by screen filtration pressure (SFP) method, which was described by Swank (1961). The SFP apparatus measures the resistance to flow of a fluid in mmHg as the blood is forced at a steady rate through a screen with multiple micro-pores 20×20 micra square and approximately 20 micra deep. Whole blood was used in SFP method, so destruction or injury of plateles which may occur during centrifugation to collect platelet rich plasma are able to avoid using this method. Nineteen human subjects, aging from 24 to 60 years, 11 males and 8 females, were used. Variations of SFP of blood added with 1/10 volume of 3×10-5 molar of ADP were less than 20 percent of the average value in all cases. So the repeated variability of SFP method was not so high and SFP method may be valuable for clinical use. In pores of used screen large number of aggregated platelets masses and few red blood cells were detected. The finding suggests that SFP is mainly due to grade of aggregated platelet mass in blood. Other factors which may influence of SFP were discussed.
