How is dx of PNH?

- Flow cytometry- to look for CD59 (MIRL) and CD55 (DAF), absence or reduced expression of both CD59 and CD55 on RBCs is diagnostic. - FLuorescent AERolysin (FLAER) a reagent derived from the bacterial toxin aerolysin, which binds directly to the GPI anchor - PNH leukocytes have a low leukocyte alkaline phosphatase (LAP) score, which is similar to that of CML