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a precursor in the granulocytic series, being a cell intermediate in development between a promyelocyte and the mature, segmented (polymorphonuclear) granular leukocyte, and having a U-shaped nucleus.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


A transitional form of myelocyte with nuclear construction that is intermediate between the mature myelocyte (myelocyte C of Sabin) and the two-lobed granular leukocyte.
Synonym(s): juvenile cell
[meta- + G. myelos, marrow, + kytos, cell]
Farlex Partner Medical Dictionary © Farlex 2012


A cell similar in shape, but slightly smaller (10 to 16 µm in diameter) than a myelocytes, which has a central or eccentric, indented kidney bean nucleus. The chromatin is usually coarsely clumped, and there is no nucleolus; the N:C ratio is 1.5:1 to 1:1. The abundant, pink or colourless cytoplasm may contain rare reddish-purple azurophilic (primary) granules and/or many fine, lilac, neutrophilic (secondary/specific) granules.

The metamyelocyte corresponds to the M5 stage of a maturing granulocyte, which is morphologically between a myelocyte (M3 or M4) and a PMN (M6 or M7).
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


A transitional form of myelocyte with nuclear construction that is intermediate between the mature myelocyte (myelocyte C of Sabin) and the two-lobed granular leukocyte.
Synonym(s): juvenile cell.
[meta- + G. myelos, marrow, + kytos, cell]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
Number Percentage of cases of cases (%) Peripheral blood smear Monocytosis 05 18.5 Nucleated RBC 06 22.2 Bone marrow aspirate cytology Plasma cells with abnormal inclusions 04 14.8 Dysmyelopoiesis 01 3.7 Eosinophilia 04 14.8 Free floating cytoplasm With LD bodies 01 3.7 Without LD bodies 04 14.8 Intracellular LD bodies in cells other than histiocytes (polymorph, 02 7.4 metamyelocyte, and megakaryocyte) Bone marrow biopsy (total 19 cases) Necrosis 02 10.5 Granuloma 01 5.2 TABLE 4: Atypical bone marrow findings observed in leishmaniasis.
Megaloblastic Anaemia- Megaloblasts, Giant Stab and Metamyelocyte in BM Aspirate (100x)
The positive smear result was defined as per the International Consensus Group criteria, which included RBC morphology at 2+ or greater, malaria, giant PLTs at moderate or greater, PLT clumps at greater than rare/occasional, Dohle bodies/ toxic granulation/vacuoles at moderate or greater, blasts at 1 or greater, metamyelocytes at greater than 2, myelocytes/promyelocytes at 1 or greater, atypical lymphocytes at greater than 5, NRBCs at 1 or greater, or plasma cell at 1 or greater.
(8) Positive smears were determined following the criteria of the consensus group: red blood cell (RBC) morphology of either 2+/moderate or greater; any positive finding related to malaria; platelet morphology (giant platelets) of either 2+/moderate or greater; platelet clumps more frequent than rare/occasional; Dohle bodies, toxic granulation, or vacuoles of either 2+/moderate or greater; and presence of abnormal cell types (blast [greater than or equal to]1, metamyelocyte >2, myelocyte/ promyelocyte [greater than or equal to]1, atypical lymphocytes >5, nucleated RBC [greater than or equal to] 1, and plasma cells [greater than or equal to]1).
33) patients had dysmyelopoeisis which included abnormal shaped nuclei, folded, cleaved nuclei, giant metamyelocyte, myelocyte, pseudo pelger heut anomaly, vacuolisation of the cells and maturation arrest.
Counts: Neutrophils: 61, Lymphocyte: 07, Monocyte: 06, Eosinophil: 05, Basophils: 04, Band forms: 03 Metamyelocyte: 04, Myelocyte: 04, Blast: 06, Platelets count: 4 Lakhs/Cu mm.
The blood cell count showed anemia and thrombocytopenia with the following indexes: hemoglobin, 8.7 g/dL; platelets, 23 x [10.sup.9]/L; white blood cells, 6.7 x [10.sup.9]/L; white blood cell differential: segmented neutrophils, 40%; bands, 34%; lymphocytes, 8%; monocytes, 8%; metamyelocytes, 3%; myelocytes, 3%; and nucleated red blood cells, 4%.
* Immature granulocytes (includes promyelocytes, myelocytes, metamyelocytes)
Laboratory investigations showed haemoglobin 5.7gm./dl; Total leukocyte count 614.8x10 9 /l, Myeloblast 65%, Promyelocytes 10%, Myelocytes 26%, Metamyelocytes 18%, Band cells 4%, Neutrophils 30% and Lymphocytes 7%: ESR 2mm, platelets 709x10 12 /L.
The patient's complete blood count revealed a hemoglobin of 10.2 g/dL, hematocrit of 33% and platelets of 357 x [10.sup.9]/L, and a corrected WBC count due to the presence of nucleated red blood cells of 60.7 x [10.sup.9]/L including 50% neutrophils, 19% lymphocytes, 10% bands, 7% myelocytes, 7% metamyelocytes, 1% promyelocytes, 5% monocytes, and 1% blasts.
His initial labs were also notable for an elevated white blood cell count of 51k/cumm (normal 6-18), with 38% bands, 5% myelocytes, and 8% metamyelocytes, an ammonia of 211mCmol/L (normal 11-35), and a lactate of 1.8mmol/L (normal 0.5-1.6).