Erythrocyte Maturation

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Figure 3.1 Erythrocyte sequence: pronormoblast.

All photomicrographs are ×1000 original magnification with Wright-Giemsa staining unless stated otherwise.

Pronormoblast

Proerythroblast
Rubriblast
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Figure 3.2A Pronormoblast.
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Figure 3.2B Schematic of pronormoblast.
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Figure 3.2C Electron micrograph of pronormoblast (×15,575).

SIZE: 12 to 20 μm

NUCLEUS: Round to slightly oval

Nucleoli: 1 to 2

Chromatin: Fine

CYTOPLASM: Dark blue; may have prominent Golgi

N:C RATIO: 8:1

REFERENCE INTERVAL:

Bone Marrow: 1%

Peripheral Blood: 0%

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Figure 3.3 Erythrocyte sequence: basophilic normoblast.

Basophilic normoblast

Basophilic Erythroblast
Prorubricyte
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Figure 3.4A Basophilic normoblast.
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Figure 3.4B Schematic of basophilic normoblast.
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Figure 3.4C Electron micrograph of basophilic normoblast (×15,575).

SIZE: 10 to 15 μm

NUCLEUS: Round to slightly oval

Nucleoli: 0 to 1

Chromatin: Slightly condensed

CYTOPLASM: Dark blue

N:C RATIO: 6:1

REFERENCE INTERVAL:

Bone Marrow: 1% to 4%

Peripheral Blood: 0%

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Figure 3.5 Erythrocyte sequence: polychromatic normoblast.

Polychromatic normoblast

Polychromatic Erythroblast
Rubricyte
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Figure 3.6A Polychromatic normoblast. The blue color of the cytoplasm is becoming gray-blue as hemoglobin is produced.
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Figure 3.6B Schematic of polychromatic normoblast.
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Figure 3.6C Electron micrograph of polychromatic normoblast (×15,575).

SIZE: 10 to 12 μm

NUCLEUS: Round

Nucleoli: None

Chromatin: Quite condensed

CYTOPLASM: Gray-blue as a result of hemoglobinization

N:C RATIO: 4:1

REFERENCE INTERVAL:

Bone Marrow: 10% to 20%

Peripheral Blood: 0%

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Figure 3.7 Erythrocyte sequence: orthochromic normoblast.

Orthochromic normoblast

Orthochromic Erythroblast
Metarubricyte
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Figure 3.8A Orthochromic normoblast. The gray-blue color of the cytoplasm is becoming salmon as more hemoglobin is produced.
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Figure 3.8B Schematic of orthochromic normoblast.
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Figure 3.8C Electron micrograph of orthochromic normoblast (×20,125).

SIZE: 8 to 10 μm

NUCLEUS: Round

Nucleoli: 0

Chromatin: Fully condensed

CYTOPLASM: More pink or salmon than blue

N:C RATIO: 0.5:1

REFERENCE INTERVAL:

Bone Marrow: 5% to 10%

Peripheral Blood: 0%

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Figure 3.9 Erythrocyte sequence: polychromatic erythrocyte (reticulocyte).

Polychromatic erythrocyte

Diffusely Basophilic Erythrocyte
Reticulocyte
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Figure 3.10A Polychromatic erythrocyte. Sometimes appears “lumpy” and larger than mature red blood cells. Slight gray-blue color persists (arrows) while the cell attains full hemoglobinization.
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Figure 3.10B Scanning electron micrograph of polychromatic erythrocyte (×5000). Note that the reticulocyte is a very deformable cell, giving it a “lumpy” appearance by scanning electron microscopy.

SIZE: 8 to 8.5 μm

NUCLEUS: Absent

Nucleoli: NA

Chromatin NA

CYTOPLASM: Color is slightly more blue/purple than the mature erythrocyte

N:C RATIO: NA

REFERENCE INTERVAL:

Bone Marrow: 1%

Peripheral Blood: 0.5% to 2.0%

NOTE: When stained with supravital stain (e.g., new methylene blue), polychromatic erythrocytes appear as reticulocytes (contain precipitated ribosomal material; see Figure 12.5A).

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Figure 3.11 Erythrocyte sequence: erythrocyte.

Erythrocyte

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Figure 3.12A Erythrocyte. The mature erythrocyte has lost the blue-gray color and is salmon colored as hemoglobinization is complete.
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Figure 3.12B Scanning electron micrograph of erythrocyte (×2500).

SIZE: 7 to 8 μm

NUCLEUS: Absent

Nucleoli: NA

Chromatin: NA

CYTOPLASM: Salmon with central pallor of about one-third of the diameter of the cell

N:C RATIO: NA

REFERENCE INTERVAL

Bone Marrow: NA

Peripheral Blood: Predominant cell type

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Figure 3.13 Erythrocyte sequence with: (A) pronormoblast; (B) basophilic normoblast; (C) polychromatic normoblast; (D) orthochromic normoblast; (E) polychromatic erythrocyte; and (F) erythrocyte.