EXPLORE is a multi-center study designed to examine the frequency of Paroxysmal Nocturnal Hemoglobinuria in patients with aplastic anemia (AA), myelodysplastic syndrome (MDS) and other bone marrow failure disorders. Current published guidelines recommend that patients with aplastic anemia, refractory anemia-myelodysplastic syndromes, and patients with any one of the following - venous thrombosis involving unusual sites, hemoglobin in the urine, intravascular hemolysis without antibodies, or episodic abdominal or swallowing pain and hemolysis - should be screened for PNH.1 The test for PNH requires only a small sample of the patient's blood from a vein in the arm for flow cytometry. The EXPLORE (Enhanced EXamination of PNH with Laboratory Observations and REsearch in Bone Marrow Disorders) study expects to initially engage approximately 200 hematologists to enroll an estimated 2,000 patients. Patients with any evidence of AA, MDS, or other bone marrow failure disorders will be asked to give informed consent to enter into the study's screening phase. An initial peripheral blood draw will be used for hematological evaluation. Patients who test positive for the PNH clone may be asked to participate in two-year follow-up to monitor symptoms and conduct hematological assessments. This study will mark the first systematic effort to determine the presence of the PNH blood cell clone in patients with AA, MDS, or other bone marrow failure disorders. The study is currently enrolling patients in US; with plans to expand the study to Europe and Asia.

EXPLORE Inclusion Criteria:

• 18 and older
• Diagnosed with
• Aplastic Anemia
• Myelodysplastic syndromes, or
• Other bone marrow failure disorders
• Informed Consent