(MDS, formerly known as “preleukemia”) are a diverse collection of hematological conditions united by ineffective production of blood cells and varying risks of transformation to acute myelogenous leukemia. Anemia requiring chronic blood transfusion is frequently present.

==Differential Diagnosis and Workup==

The differential diagnosis is that of [[anemia]], [[thrombocytopenia]], and/or [[leukopenia]].  Usually, the elimination of known [[etiologies]] of [[cytopenias]], along with a [[dysplastic]] bone marrow, is required to diagnose a myelodysplastic syndrome.

Investigation:

* [[Full blood count]] and examination of [[blood film]].  The [[blood film]] morphology can provide clues about [[hemolytic anemia]], clumping of the [[platelets]] leading to spurious [[thrombocytopenia]], or [[leukemia]].

* Blood tests to eliminate other common causes of [[cytopenias]], such as [[lupus]], [[hepatitis]], [[B12]], [[folate]], or other [[vitamin]] deficiencies, [[renal failure]] or [[heart failure]], [[HIV]], [[hemolytic anemia]], [[monoclonal gammopathy]].  [[Age-appropriate cancer screening]] should be considered for all [[anemic]] patients.

* [[Bone marrow examination]] by an experienced [[hematopathologist]].  This is required to establish the diagnosis, since all hematopathologists recognize a dysplastic marrow as the key feature of myelodysplasia.

* [[Cytogenetics]] or chromosomal studies.  This is ideally performed on the bone marrow aspirate.  These require a fresh specimen, since live cells are induced to enter [[metaphase]] to enhance [[chromosomal]] staining.

* [[Flow cytometry]] is helpful to establish the presence of any [[lymphoproliferative]] disorder in the [[marrow]]