The Chronolog SPA-2000 is designed to run Hypotonic Shock Response Assay (HSR) and the Extent of Shape Change Assay (ESC) on Platelets.

The Hypotonic Shock Response or Osmotic Reversal Reaction measures the swelling of platelets after the injection of water into the sample.

The Extent of Shape Change measures the change in Optical Density of a platelet sample caused by the addition of ADP. After the addition of ADP, the platelets change from discoid shape to sperical causing an increase in optical density.