Platelet swirling is a noninvasive method for testing the quality of Platelet-rich plasma (PRP). Platelet swirling is caused by light diffraction due to the alignment of normal discoid shaped platelets. When these discoids align light that is diffracted creates a cloudy or swirling like appearance.
Read more about Platelet Swirling: Perform A Platelet Swirling Test, Further Reading