Diagnosis of PNH typically involves flow cytometry to assess the presence of GPI-anchored proteins such as CD55 and CD59 on the surface of red blood cells and other hematopoietic cells. In PNH, these proteins are absent or significantly reduced, leading to increased susceptibility of red blood cells to complement-mediated lysis. This absence can be detected histologically by staining techniques and using monoclonal antibodies specific to these proteins.
