1. Department of Pediatrics; Memorial Sloan Kettering Cancer Center; New York New York
2. Cohen Children's Medical Center of New York; New Hyde Park New York
3. Hemoglobin Diagnostic Reference Laboratory; Departments of Medicine; Pathology and Laboratory Medicine; Boston Medical Center; Boston Massachusetts
4. Department of Pediatrics; Duke University Medical Center; Durham North Carolina
5. Department of Pediatrics; Medical College of Wisconsin; Blood Research Institute; Children's Research Institute; Milwaukee Wisconsin
6. Department of Hematology; St. Jude Children's Research Hospital; Memphis Tennessee