CD63 and autosomal dominant polycystic kidney disease: The morphology and size characterization of FPCM from three control and four patient urine samples showed lipid-bilayer spheroids of 30–150 nm by EM and DLS (Figure 3A,B), whereas FC analysis showed 45 ± 5% of CD63+ particles in two and four control and ADPKD samples, respectively (Figure 3C).