This document describes various abnormalities that can be seen in red blood cells during a blood smear examination. It defines different types of anisocytosis (variation in red blood cell size), anisochromia (variation in hemoglobin concentration), and abnormal red blood cell shapes that may indicate underlying hematological disorders. Various intracellular inclusions and remnants such as Howell-Jolly bodies, Heinz bodies, and Pappenheimer bodies are also described.

1. JOSE R.VILLARINO, RMT

2.  ANISOCYTOSIS – variation in RBC size
 Normocyte = measures 6.2 – 8.2 u (7.2 u)
 Microcyte = less than 6 u
 Macrocyte = measuring 8 – 9 u
 Megalocyte = measures 9 – 12 u

3.  Normochromic – peripheral ring of Hgb
surrounding an area of pallor
 Hypochromic – thin peripheral Hgb ring with
an enlarged area of pallor
 Ex. Annulocyte
 Hyperchromic – RBC appears thicker than
normal, stains evenly through out the cell and
lacks the area of pallor.
 Ex. Spherocyte

4.  Anisochromia / dimorphic anemia – blood
picture showing both normochromic and
hypochromic red blood cells.
 Ex. Sideroblastic anemia, blood transfusion
and on Iron therapy
 Polychromasia / polychromatophilia – a bluish
gray color of the RBC on Wright’s stain smear
due to presence of RNA.

5.  Residual RNA indicates immaturity of cell
 On supravital staining with Brilliant Cresyl Blue
or New Methylene Blue, the RNA combines
with the stain to form the dye-
ribonuceloprotein complex which appears as a
lacework pattern called the reticulum and
thus calling the said cell as RETICULOCYTE.
 Polychromasia = Reticulocyte

6.  Target cell – also called the leptocyte ,the
Mexican hat cell or the codocyte
 An RBC with a peripheral ring of Hgb plus a
central condensation of Hgb in the area of
pallor or “ bull’s eye appearance “
 Found in patients with hemoglobinopathy and
thalassemias

7.  Secondary to Developmental Macrocytosis
 Secondary to Membrane Abnormalities
- Spherocyte – small, spherical or rounded shape
RBC. They appear thicker than No and are
hyperchromic with increase osmotic fragility.
- Echinocyte – crenated RBC, small rbc with
uniformly sized, blunt projections evenly
distributed. Artifactual due to hypertonic
solutions or excessive air drying of smears

8. - Burr cell – RBC with unevenly spaced spicules,
more pointed rather than blunt
- Acanthocyte – spur cell, RBC with club-shaped
(swollen) spicules, or prominent irregular
thorn-like projections
- Stomatocyte – slit-shaped or mouth-like areas
of pallor. On wet mounts, appear to be
uniconcave or “rice-bowl” appearance

9. - Codocyte – target cell, codocyte, Mexican hat
cell or “ bulls-eye appearance”
- Ovalocyte – also called elliptocyte, rbc with
cigar, oval or elliptical shapes.True ovalocytes
are to be distinguished from
pseudoelliptocytes where true ovalocytes
arranged at random order. Pseudo follow one
uniform direction usually due to poor smear
preparation.

10. - Schistocyte or schizocyte – fragments of
destroyed RBC indicating trauma or a
hemolytic process
- Keratocyte – RBCs with horn-like projections,
also called helmit cells
- Dacryocyte – teardrop looking RBCs , they
appear swollen , pear-shaped
- Semi-lunar bodies – pale pink, crescent shaped
RBCs ( ghost cells )

11. - Sickle cell – depranocyte or meniscocyte sickle-
shaped or crescent-shaped RBC. The abnormal
Hgb S during decreased oxygen tension will
crystallize or polymerize causing the cell to
sickle shape
- Hgb CC crystals – hexagonal shaped crystals
with blunt ends
- Hgb SC crystals – “ Washington monument
appearance of crystals”

12.  Developmental Organelles
- Howell Jolly bodies – single blue bodies, DNA
remnants. Seen in Pernicious anemia
- Basophilic stipplings also known as punctuate
basophilia – fine to coarse, blue to purple
granules scattered homogenously in the
cytoplasm. Remnants of ribosomal RNA and
indicates disturbed erythropoiesis.

13. - Pappenheimer bodies or siderotic granules iron
containing granules that appear dark-staining
on Wright’s stain found lying on the periphery
of the cell in groups. On Perl’s Prussian Blue
stain, these bodies stained positively indicating
iron content.
- Cabot rings – ring-like, loop-like, figure of 8
staining reddish violet in Wright’s stain.
Remnants of mitotic spindle or fragment of the
nuclear membrane.

14. - Heinz bodies – dense, highly refractile granules
representing precipitated or denatured globin
associated with the unstable Hgb. Seen in
patients with Glucose 6 Phosphate
dehyrogenase (G6PD) deficiency
- Hemoglobin H inclusions – greenish colored
inclusions on BCB staining giving rise to the
characteristic “golf-ball pattern”

15. - Malarial parasites – presence of malarial
parasite stages ( ring forms, gametocytes etc.)
or pigments (stipplings) either on Wright’s or
Giemsa stained smears.
- Babesia microtii – like malaria, it is an RBC
infecting parasite though “tick-borne”. Only
seen as ring forms in groups of 2 (rabbits ear) or
4 (Maltese cross appearance)