Hematology: Supravital Stains and Erythropoiesis

Supravital Stains for Reticulocytes

• Supravital stains are used to identify reticulocytes in a Wright-stained smear.
• New methylene blue and brilliant cresyl blue are examples of supravital stains.

Erythroid Precursor Maturation

• As erythroid precursors mature, the overall and nuclear cell diameters decrease.
• Chromatin condenses and clumps.
• Nucleoli disappear.
• Cytoplasm changes from blue to gray-blue then to salmon pink.

N:C Ratio

• N:C ratio is a morphological feature to identify and stage RBC and WBC precursors.
• It's a visual estimate of the nucleus area relative to the cytoplasm area.
• If areas are equal N:C ratio is 1:1
• If nucleus is less than 50% of the cell, N:C ratio is lower (e.g., 1:5).
• If nucleus is more than 50% of the cell, N:C ratio is higher (e.g., 3:1).

Basophilia

• Basophilia refers to the blueness of a particular part of the cell.
• It's due to acidic components attracting basic stains like methylene blue.
• Degree of cytoplasmic basophilia correlates with ribosomal RNA quantity.

Eosinophilia/Acidophilia

• Eosinophilia/Acidophilia is the pinkness of a particular part of a cell.
• It's linked to the accumulation of basic components that attract acid stains like eosin.
• As RBC matures, eosinophilia correlates with hemoglobin accumulation, which decreases basophilia.

Rubriblast (Pronormoblast) Characteristics

• Size: 12-19 μm
• Nucleus: round to slightly oval, thin nuclear membrane, centrally or slightly eccentric.
• Nucleoli: 1-2
• Cytoplasm: small, dark blue, homogenous (due to ribosome concentration).
• N:C ratio: 4:1 (Turgeon)
• This cell (rubriblast) gives rise to prorubricytes.
• Rodak (8:1): very far away, not yet wed.
• Earliest recognizable precursor using light microscopy; not the youngest precursor.