Myelocytes represent the developmental stage of myelopoiesis between promyelocytes and metamyelocytes. Myelocytes are small with a diameter of 12-18 µm and have few primary granulues if any. The nuclear chromatin is coarser and contains at most one nucleolus. They are best distinguished by the form of the nucleus which is only slightly indented. The spectrum of myelocytes is large and includes immature forms with basophilic cytoplasm to mature forms with light pink cytoplasm. Secondary granules, respectively neutrophilic, eosinophilic or basophilic granules appear in myelocytes.
Please note! The preliminary stages with eosinophilic and basophilic granules are classified as eosinophilic and/or basophilic granulocytes in the manual differential count.

Occurrence in the peripheral blood:
- In all myeloproliferative neoplams, particularly in chronic myelocytic leukemia and myelofibrosis.
- In severe infections (leukemoid reaction)..
- In abnormalities of the bone marrow blood barrier.