I'm assuming that these are all words ending with -cyte (though I also considered 'myeloblast').

Metamyelocyte - an overview | ScienceDirect Topics
https://www.sciencedirect.com › topics › metamyelocyte

A small fraction of promyelocytes, myelocytes, and metamyelocytes escape the marrow and are found in the blood, and these can be measured by certain hematology ...


https://pubmed.ncbi.nlm.nih.gov/6418231/
The prognostic significance of a left shift in the peripheral blood at the time of diagnosis of acute lymphocytic leukemia was investigated by a retrospective analysis of 109 patients treated on the same protocol in a single institution. Left shift was defined as the presence of 1% or more of metamyelocytes, myelocytes, or promyelocytes.