Rubriblast

Also called a pronormoblast.

Large nucleus that fills most of the cell and has a fine chromatin patter with 1 to 2 nucleoli

Prorubricyte

Also called Basophilic Normoblast.

Nucleus is large, fills about 3/4 of the cell, has courser chromatin pattern, slight perinuclear halo.

Rubricyte

Also called Polychromatic Normoblast.

Shades of blue an gray cytoplasm; coloration due to beginning of hemoglobin production. Nucleus is smaller, round, clumped patter.  Last red cell stage capable of cell division.

Metarubricyte

Also called Orthochromatic Normoblast.

Cytoplasm turns pink due to hemoglobin.

Nuclues is round and pyknotic (condensed chromatin).

Cells are counted as Nucleated Red Blood Cells (NRBC) when seen in blood smears.

Reticulocyte

Also called Polychromatic Erythrocyte.

First non-nucleated red blood cell.

Stains slightly blue with Wright's Stain.

If seen in peripheral blood it indicates that the bone marrow is increasing red cell production.

Red Blood Cell

Also called a Erythrocyte.

Very small in size.

Stains red due to hemoglobin.

Cell shape is a biconcave disc which gives a slight pale appearance in the cell's center.