The Hematology Service provides hematology consultations for patients at the Clinical Center and participates in the training of hematology fellows. Patients with a broad range of hematologic disorders must be available in order for the senior staff of the Service to maintain clinical expertise and to provide the breadth of experience necessary for the fellowship program. The purpose of this protocol is to meet these needs by allowing the Hematology Service to see patients with a spectrum of hematologic diseases not studied on existing research protocols at the NIH. These patients will be evaluated over the course of several outpatient visits and returned to the care of their referring physicians.This study was developed to evaluate and possibly treat patients with blood disorders. The Hematology Service of the National Institutes of Health is responsible for the care of patients participating in research studies. In addition the Hematology Service also provides consultation for small groups of patients with blood disorders that have not been diagnosed or that may need special testing.

This study will also provide doctors at the NIH the opportunity to learn more about a wide range of blood disorders and conditions. Patients participating in this study will be evaluated over the course of several outpatient visits and will continue to be cared for by their regular physician.

The Hematology Service provides hematology consultations for patients at the Clinical Center and participates in the training of hematology fellows. Patients with a broad range of hematologic disorders must be available in order for the senior staff of the Service to maintain clinical expertise and to provide the breadth of experience necessary for the fellowship program. The purpose of this protocol is to meet these needs by allowing the Hematology Service to see patients with a spectrum of hematologic diseases not studied on existing research protocols at the NIH. These patients will be evaluated over the course of several outpatient visits and returned to the care of their referring physicians.

• INCLUSION CRITERIA:

The patient must have or be suspected of having a blood disorder.

The patient must be clinically stable enough for outpatient evaluation.

The patients must be referred from a physician outside the NIH who will continue to provide the patient's primary medical care.

EXCLUSION CRITERIA:

Inability of patient, parent or legal gaurdian to provide informed consent.