Apparatus and methods for monitoring platelet quality are disclosed. A bag of platelet concentrate is oriented in a desired manner on a transparent surface that is illuminated from one side with a light source. A clamp applies pressure to a desired portion of the bag to temporarily manipulate a predetermined portion of the bag and therefore the fluid in the bag in a known and repeatable manner. A flow inducing member applies pressure to the bag to thereby cause a turbulent flow of the fluid from the bag through a flow path. A detector records optical characteristics of light diffracted by the flowing particles, which is analyzed by software to derive a score correlating to the quality of the platelets. Platelet swirl is scored as a measure of platelet quality where more resting, discoid platelets result in a higher score.
