Bone Marrow

Normal Bone Marrow

  • Illustrated in the photograph is a normal bone marrow smear stained with Wright/Giemsa stain. Note the evenly distributed cells with normal maturation in both the myeloid and erythroid maturation sequences.
  • An estimation of the percentage composition of cells can be made by experienced observers from scanning of multiple fields. In some instances a detailed differential count of 300 or more cells must be made.
  • In normal bone marrows, the myeloid to erythroid ratio (M:E ratio)ranges from 1.2:1 to 5:1.
  • A ratio of less than 1.2:1 indicates depressed leukopoiesis or erythroid hyperplasia. Ratios of 6:1 or greater usually indicates infection, erythroid hypoplasia, or chronic myelogenous leukemia.
  • An assessment of the overall cellularity is also useful. In general, cellularity of less than 25% indicates hypoplasia; greater than 75% indicates hyperplasia.

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