This document summarizes the morphology of different blood cells as seen on a blood film. It describes the components of blood including red blood cells, white blood cells such as neutrophils, lymphocytes, monocytes, eosinophils and basophils, as well as platelets. Examples of each cell type are shown along with descriptions of their distinguishing characteristics. Potential artefacts that can occur on blood films due to issues like improper fixation, heating or prolonged storage are also outlined.

1. The morphology of Blood cells
Dr.Mohammad Al-Fararjeh

2. Composition of the blood
 The circulating blood is composed of plasma
and cells.
 The cells are red cells (or erythrocytes),
white cells (or leucocytes) and platelets.
 Blood cells can be identified in blood films
stained with a mixture of basic and acidic
dyes.
 Normal white cells are divided into
polymorphonuclear leucocytes (or
granulocytes) and mononuclear cells.

3. White blood cells
 There are three types of
granulocyte named
according to their
staining characteristics in
blood films. They are
neutrophils,eosinophils
and basophils.
 Mononuclear cells are
divided into
lymphocytes and
monocytes.

4. Neutrophils
 The neutrophils in
the circulating
blood are mainly
mature segmented
neutrophils.

5. Band form Neutrophils
 There are smaller
numbers of cells of
neutrophil lineage with
non-segmented nuclei.
They are referred to as
neutrophil band cells or
band forms. They are
less mature than
segmented neutrophils.
 An increased number
of band cells is referred
to as a'left shift'.

6. Eosinophil
 One eosinophil -
mature. Normal
blood - 100X.
 Orange color
granules.
 Bi-lobed nucleus.

7. Basophil
 One mature
basophil.
 Blackish granules
overlying the
nucleus.

8. Normal lumphocytes
 Lymphocytes are the
smallest WBC.
 They have large
condensed nucleus,
with a scanty bluish
cytoplasm.

9. Normal monocyte
 Monocytes are the
largest WBC.
 The nucleus is
slightly indented .
 The cytoplasm is
abundant, sky blue
in color.
 Some have vacuoles
in the cytoplasm.

10. Red cells
 Normal red cells or
erythrocytes show
only slight variation
in size and shape.
The blood film
should be examined
in the area where
the red cells are
touching but not
often overlapping.

11. Red cells
. In this area many red
cells have an area of
central pallor which may
be up to a third of the
diameter of the cell. This
is consequent on the
shape of a normal red
cell, which resembles a
disc that is thinner in the
centre.

12. Platelets
 Normal platelets are
also apparent. They
are small not clear
fragments between
the red cells
containing small
purple-staining
granules.

13. Platelet ribbon
A string of platelets
or Platelet Ribbon.
This is the
appearance of normal
platelets when being
shed by a
megakaryocyte into
the marrow sinus.
The ribbon then
breaks up into
numerous small
platelet fragments.
Normal blood - 100X

14. Platelet aggregates
 Platelet aggregates may
be
composed of apparently
intact
platelets, degranulated
pale grey platelets or a
mixture of both, as in
this example. If the
platelet count is low it is
essential to examine the
blood film carefully for
platelet aggregates.

15. Platelet satellitism
 Platelet satellitism
describes the
phenomenon of
adherence of platelets to
white cells.
 It is an in vitro
phenomenon of no
clinical significance.
However it is important
that it is detected since
the platelet count will be
factitiously low.

16. Nucleated epithelial cells
 Extraneous non-haemopoietic
cells are sometimes seen in
blood films. These include
epithelial cells which are
readily identified from their
abundant sky-blue cytoplasm
and small central nucleus.
They are more often seen
if capillary blood is obtained
by puncture than when a film
is made from venous blood.

17. Endothelial cells
 Endothelial cells are occasionally
seen in films prepared from
venous blood samples. They
have rather pleomorphic oval
nuclei with a grooved surface.
The cytoplasm is scanty and the
cell outline is irregular. They tend
to occur in clumps. It is
important not to confuse normal
endothelial cells with carcinoma
cells which are also very
occasionally seen in the
circulating blood.

18. Artefacts
 Fixation artefact is the
term used for the
artefact that occurs
when there is water in
the methanol used for
fixation of the blood
film.This leads to
refractile rings in red
cells and makes it quite
impossible to assess red
cell morphology.

19. Heat artefact
 Inadvertent heating of a blood
sample, for example during
transport in a hot car, can lead to
a heat artefact.
 Red cells bud off vesicles and
microspherocytes seen.
 White cells disintegrate
 proteins coagulate, producing
weakly basophilic particles, which
are similar in size to platelets.

20. Storage artefact
 Prolonged storage of blood before
making the blood film, particularly
storage at room temperature,leads to
storage artefact.
 White cells become fragile and may
form smear cells [deep red arrow].
 Neutrophil nuclei round up and form
homogeneous round masses or a
single mass [blue arrow].These cells
have a resemblance to NRBC.
 Red cells undergo an echinocytic
change or crenation.