Bone marrow failure patients had no sign of intravascular hemolysis and only one case (50%) was found lacking of one CD on one lineage. Among patients who had a certain diagnosis of PNH (having two CD on two lineages) the symptoms hemoblobinuria make up 62.5% and Hamdacie test posive make up 75%. Conclusion: Technique for indentyfying immunophenotypes by Flow cytometry can easily and correctly screen PNH disease.