Erythrocytic Developmental Series Hematology Review 295
RUBRIBLAST TERMINOLOGY NORMOBLAST TERMINOLOGY KEY CHARACTERISTICS
Rubriblast
Prorubricyte
Rubricyte
Metarubricyte
Reticulocyte
Mature erythrocyte
Pronormoblast
Basophilic normoblast
Polychromatophilic normoblast
Orthochromic normoblast
Polychromatophilic erythrocyte
Mature erythrocyte
14–24 m. N:C ratio 8:1. Royal blue cytoplasm. Fine chromatin.
1–2 nucleoli. Normally confined to bone marrow.
12–17 m. N:C ratio 6:1. Chromatin is coarser with slightly
visible parachromatin. Nucleoli usually not visible. Normally
confined to bone marrow.
10–15 m. N:C ratio 4:1. Cytoplasm is polychromatophilic due
to hemoglobin production. Chromatin is clumped with distinct
areas of parachromatin. Last stage to divide. Normally confined
to bone marrow.
8–12 m. N:C ratio 1:2. Nucleus is pyknotic. Last nucleated stage.
Normally confined to bone marrow.
7–10 m. No nucleus. Cytoplasm is diffusely basophilic (bluish
tinge). Reticulum seen with supravital stain. 0.5%–1.5% of
RBCs in adult peripheral blood.
7–8 m. Biconcave disk. Reddish-pink cytoplasm with area of
central pallor 1/3 diameter of cell.