This document describes normal red blood cell morphology and various abnormalities that can occur. A normal red blood cell is biconcave and disk-like in shape, containing hemoglobin and lacking a nucleus. Abnormalities include variations in size (anisocytosis), shape (poikilocytosis), and inclusions within red blood cells. Specific abnormal RBC shapes discussed include spherocytes, ovalocytes, burr cells, crenated cells, schistocytes, and sickle cells. Causes of these abnormalities and other findings like basophilic stippling are also summarized.

2. Red cell morphology

3. Normal Red Cell
Fragile, Biconcave, disk like structure.
Have smooth round surface
Diameter ranges from 7.5-7.8µm.
Appears to be of the same size as the nucleus of the small
lymphocyte.
Have no nucleus
Whole cell is filled with the HAEMOGLOBIN.
The red colour of red cells is due to the presence or haemoglobin
RBCs survive for approximately 120 days in the peripheral blood

4. Normal red cell

5. Normocytic & Normochromic
•Normocytic: The term used to express RBCs of normal size is
normocytic.
•Normochromic: Mature red blood cells, under normal
circumstances, will also have an appropriate hemoglobin content, giving
them a red-orange appearance on Wright-stained smears. These cells
will display a central pallor no larger than 3 microns in diameter. This
normal morphology is indicated by the term normochromic.
•It is paramount for RBCs to contain an adequate amount of
hemoglobin for the purpose of transporting oxygen to the tissues and
carbon dioxide back to the lungs.

6. ABNORMALITIES OF RED CELLS
3 types of abnormalities may occur in red blood cells
i.Anisocytosis: If the size of RBC varies, in the same blood film,
beyond normal limits, it is termed anisocytosis.
ii.Poikilocytosis: When the shapes of RBCs vary more than
expected in normal individuals, in the blood film, it is termed
poikilocytosis.
iii.INCLUSIONS IN RBC: abnormal structures present in red
cells having certain staining charecteristics

7. Anisocytosis:
Poikilocytosis:

8. Anisocytosis:
Variations in size are as follows:
1)MACROCYTOSIS: When the average size of RBC is
more than normal, it is termed macrocytosis.
Causes Of Macrocytosis:
liver disease
megaloblastic anaemia
aplastic anaemia,
obstructive airway disease
excess of alcohol,

9. Cont…
MIROCYTOSIS: When the average size of RBC in
a blood film is less than normal it is termed
microcytosis.
Causes Of Microcytosis:
iron deficiency anaemia
thalassaemia.
There will decrease in MCV.
Should be distingused from red cell fragmentation. If in
association with decrease in MCV it will be microcytosis.

10. POIKILOCYTOSIS
Abnormality in shape may be of the following types:
1.Spherocytes
2.Ovalocytes
3.Burr cells
4.Crenated red cells
5.Schistocytes
6.Tear drop cells
7.Acanthocytes
8.Target cells
9.Sickle cells
10.Pencil cells:

11. Cont….
Spherocytes: small densely staining spherical red
cells with no central pallor area
Causes:
•Haemolytic anaemia
• drugs induced
•snake venom
•infection with C. perfringens
•hereditary spherocytosis
•ABO haemolytic disease of the newborn

12. CONTINU…..
Ovalocytes: these are oval shaped red cells.
About 10% RBC in a normal blood film,
particularly at the tail end, appear oval and
less commonly elliptical in shape.
Causes:
•Iron deficiency anaemia,
•megaloblastic anaemia

13. Cont….
Pencil cells: Elongated narrow red cells
Feature of iron deficiency anaemia

14. Cont….
Target : these are hypochromic red cells showing
central spot of Hb
Causes:
•Thalassaemia syndromes
•sickle cell disease
•HbC disease
•HbD disease
•obstructive jaundice
•liver disease
•postsplenectomy

15. Cont....
Sickle cells: These are thin crescent shaped, or boat
shaped cells elongated, deeply staining red cells with
pointed ends.
These may be straight, curved or of various other
shapes. These are produced by polymerisation of HbS
in sickle cell disease.,
Causes: Sickle cell disease, including sickle cell
anaemia (S/S) sickle cell/ thalassaemia,

16. Cont....
Sickle cells:

17. Cont....
Acanthocytes: Irregularly crenated cells with irregularly
spaced sharp projections. Small number of spicules of
inconstant length, thickness , shape ,irregularly disposed over
the surface of the cell.
Causes: Associated with abnormal phospholipids metabolism
or with inherited abnormalities of red cell membrane
proteins. After spleenectomy, hypospleenism and in sever
liver disease.

18. Cont….
Tear drop : Cells shaped like tear drops. It is also
called pear shaped cell.
these cells are usually found In iron deficiency
anaemia

19. Cont….
Schistocytes: These are fragmented red blood cells of
various shapes and sizes.
Cause:
Associated with red cell damage
due to
severe burns, drugs, toxins, DIC.
Also found in uraemia

20. CRENATED RED CELLS: Echinocytes or crenated cells
have evenly distributed blunt spicules of uniform size
on their surface.
A few crenated cells are seen in the blood film of
healthy subjects.
These are formed if
anticoagulated blood is
allowed to stand for long
periods

21. Cont….
Burr cells: Burr cells are also echinocytes but
their spicules are reversible.
Causes:
•Uraemia
•acute blood loss
•Pyruvate kinase deficiency

22. Cont….
STOMATOCYTOSIS
In dry films , the central biconcave area appears slit like. In wet
preparations, the stomatocyte is a cup shaped red cell.
Also occurs as an artifact because the change can be produced by
decrease pH .
They are found in:
•Hereditary stomatocytosis
•Liver disease
•Alcoholism

23. Cont…
Hypochromasia or hypochromic red cells: these are
the red cells which are deficient in Hb. They appear
ring shaped because the centeral palor is increased.
They are found in
• iron deficiency anaemia
•Thalassaemia
•sideroblastic anaemia

24. Dimorphic appearance
It is the Presence of two different populations
of red cells,
e.g:
• hypochromic cells with normal red cells, or
•hypochromic cells with macrocytic cells
Commonly seen following successful treatment for anemia and post-
blood transfusion

25. INCLUSIONS IN RBC:
Abnormal structures which are present In red cells are
called inclusions. These are normally abscent in red
cells.
These includes:
•Howell-Jolly bodies
•Cabot Rings
•Heinz Bodies
•Siderocytes
•Basophilic stippling
•Malarial parasite

26. Cont….
Howell-Jolly bodies:These are small (<1 μm in diameter)
rounded fragments of the nuclear material staining reddish-
blue to blue-black. These usually occur singly in RBC but may
be multiple. During maturation in the bone
marrow erythrocytes normally expel their nuclei, but in some
cases a small portion of DNA remains.
Causes:
•splenectomy
•Splenic atrophy
•alcoholism
•sickle cell anaemia
•megaloblastic anaemia.

27. Cont….
Cabot rings: These are Reddish-blue threadlike rings in
RBCs. These are remnants of the nuclear membrane
and appear as a ring or figure 8 pattern.
Very rare finding in patients
with Megaloblastic anemia
severe anemia's
lead poisoning
and dyserythropoiesis

28. Cont….
Heinz Bodies:
•Represent areas of denatured hemoglobin. They appear highly
refractile bodies near the pariphery of cell In unstained wet cover
glass preparation.
•With a supravital stain like crystal violet, Heinz bodies appear as
round blue precipitates.
•Presence of Heinz bodies indicates red cell injury and is usually
associated with G6PD-deficiency.

29. Heinz Bodies

30. Siderocytes:
these are red cells containing non haemoglobin iron granules.
Iron granules appear bright blue.
They are found in haemolytic anaemia.

31. Cont….
Basophilic stippling: These are fine to coarse, deep blue to purple,
small but multiple inclusions of varying sizes.
They are given the name due to purplish colour.
Normally one in 10000 cells may show basophilic stippling.
Increased no is seen in:
•Thalassaemia
•megaloblastic anaemia
•liver disease
•lead poisoning
•infections

32. Cont….
Malarial parasite:
Malarial parasite may be present in red cells in
verious forms like:
•Trophozoite
•Schizont
•gametocytes

33. ROULEAUX FORMATION
A stack like arrangement of red blood cells
in blood or in diluted suspensions of blood
in which their biconcave surfaces are next
to each other.
The RBC's here have stacked together in
long chains. This is known as "rouleaux
formation"
It happens with increased serum proteins,
particularly fibrinogen and globulins.

34. CHANGES ASSOSIATED WITH A
COMPANSATORY INCREASE IN
ERYTHROPOIESES

35. POLYCHROMASIA
Refers to having red blood cell of
multiple colors, particularly gray-
blue.
This is due to differing amounts
of haemoglobin in each cell , which
is due to inappropriate, premature
release from the bone marrow:

36. ERYTHROBLASTEMIA
The presence in the peripheral
blood of abnormally large number
nucleated red cells.
They are found in sever anemia.
Large number is characteristic of
haemolytic disease of newborn.
After spleenectamy.
Sickle cell anemia.
Leukemia .
Myelofibrosis.

37. PIMS