The PNH classification system that was proposed
here defines PNH as Stage 1 when only cells in the bone marrow are affected, Stage 2 when leukocytes in circulating blood are affected as well, and Stage 3 when erythrocytes are also affected. Stage 3 is therefore the "classical" PNH that most patients are familiar with. Do you think that's what the hematologist was referring to?
Note that many PNH patients have chronic kidney disease (CKD), which is classified in stages.