Characteristic
red blood cell abnormalities are anaemia, sickle cell anaemia and spherocytosis.
Sometimes the microscopic investigation of the red cells can be essential to
the diagnosis of life – threatening disease e.g. TTP.
ANAEMIA: this is the most
significant in red cell abnormalities. Here the oxygen carrying capacity of blood
is decreased in respect to patient's age, sex, environmental factors and
climatic factor (WHO DEFINITION). The causes of anaemia are varied, and most of
them are expressed as changes in RBC morphology. Therefore, morphological examination
of red cells using blood film is very helpful in evaluating and determining the
cause of anaemia. Normal
red blood cells stained with a Romanowsky stain are nearly uniform in size ,
shape and colour. Each
cell appears as a pink disc, about 7 microns in diameter, with a rim of
hemoglobin and a clear central area called central pallor. The central pallor
generally occupies less than one-third of cell. The red cells having normal
size and normal colour are said to be normocytic and normochromic,
respectively. Blood disorders may be indicated microscopically by changes in
the shape of red cells or by presence of inclusion body (Hoffbrand and Moss,
2011).
Blood Film
Showing Normal Blood
Abnormal Blood
a.
Anisocytosis
(variation in size)
b. Poikilocytosis (irregularities in shape)
c. Variation in colours
Hypochromia: Ring staining of cells due to poor
hemoglobin
SPHEROCYTOSIS: small dense
red cells due to cell membrane abnormalities cells show increased osmotic
fragility. (loss of biconcavity) (Bacus, 2001)
ABNORMALITIES
ASSOCIATED WITH HEMOGLOBINOPATHIES
SICKLE CELLS: severe
distortion of red cells due to aggregation of abnormal hemoglobin molecules in
reduced stage.
TARGET CELLS: cells showing
central area of density with surrounding pallor (thin cells with central
bulge).
Red cell inclusion
bodies
Nucleated
In
examination of blood film for white blood cell estimation, these white cell are seen
a.
Neutrophil
granulocytes: usually make up to 80% of the white cell count.
b.
Eosinophil
granulocytes
c.
Basophile
granulocytes : these are seen occasionally
d.
Lymphocytes:
having very little cytoplasm and large nucleus
