Developed by Duke in 1910 and bearing his name, it measured the time for bleeding to stop from a standardized wound in the ear lobe which is blotted each 30 seconds.
The PFA-100 is a system for analysing platelet function in which citrated whole blood is aspirated through a disposable cartridge containing an aperture within a membrane coated with either collagen and epinephrine or collagen and ADP.