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Preparation and Examination of Blood Smear (view source)
Revision as of 19:44, 23 February 2022
, 19:44, 23 February 2022→Erythrocyte evaluation
[[File:NWL Lab.jpg|thumb|Refractile bodies NationWide Laboratories]]
[[File:NWL Lab.jpg|thumb|Refractile bodies NationWide Laboratories]]
<u>'''Artefacts'''.</u> Stain precipitate, refractile bodies and echinocytes.
<u>'''Artefacts'''.</u> Stain precipitate, refractile bodies and echinocytes.
Echinocytes (crenated red cells). Red cells with many spiny projections which tend to be evenly spaced and uniform. This is often artefact seen in thick smears, which have taken a long time to dry, or due to excess EDTA, if the tube is not filled to the line. Echinocytes can be associated with pathological changes such as uraemia, glomerulonephritis, neoplasia and snake venom.
Echinocytes (crenated red cells). Red cells with many spiny projections which tend to be evenly spaced and uniform. This is often artefact seen in thick smears, which have taken a long time to dry, or due to excess EDTA, if the tube is not filled to the line. Echinocytes can be associated with pathological changes such as uraemia, glomerulonephritis, neoplasia and snake venom.
[[File:NWLab .jpg|thumb|Echinocytes, a small and large platelet NationWide Laboratories|alt=|left]]
'''Indicators of regeneration'''
<u>'''Anisocytosis.'''</u> Refers to variation in RBC size. Immature cells (reticulocytes) are larger than mature erythrocytes.
<u>'''Anisocytosis.'''</u> Refers to variation in RBC size. Immature cells (reticulocytes) are larger than mature erythrocytes.
[[File:NWL 2016 Labfacts inners A.jpg|thumb|Anisocytosis and Polychromasia NationWide Laboratories]]
[[File:NWL 2016 Labfacts inners A.jpg|thumb|Anisocytosis and Polychromasia NationWide Laboratories]]
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The higher the grade, the more marked the degree of regeneration in response to anaemia. Anisocytosis and polychromasia in non-anaemic patients may reflect poor oxygenation of blood due to cardiac or respiratory disease.
The higher the grade, the more marked the degree of regeneration in response to anaemia. Anisocytosis and polychromasia in non-anaemic patients may reflect poor oxygenation of blood due to cardiac or respiratory disease.
<u>'''Reticulocytes'''</u>. Immature red cells, their residual RNA and mitochondria stain with new methylene blue.
[[File:NWL 2016.jpg|thumb|Canine reticulocytes NationWide Laboratories|alt=|left]]<u>'''Reticulocytes'''</u>. Immature red cells, their residual RNA and mitochondria stain with new methylene blue.
[[File:NationWide Lab 2016.jpg|thumb|Nucleated red blood cell NationWide Laboratories]]
[[File:NW laboratories.jpg|thumb|Feline Reticulocytes NationWide Laboratories ]][[File:NationWide Lab 2016.jpg|thumb|Nucleated red blood cell NationWide Laboratories]]
<u>'''Eccentrocytes.'''</u> These are RBCs where, as a result of oxidative injury, the Hb has coalesced, usually at one side of the cell; the remainder of the cell is pale staining.
<u>'''Eccentrocytes.'''</u> These are RBCs where, as a result of oxidative injury, the Hb has coalesced, usually at one side of the cell; the remainder of the cell is pale staining.
[[File:NWLLabfacts 5.jpg|thumb|Heinz Bodies NationWide Laboratories ]]
[[File:NWLLabfacts 5.jpg|thumb|Heinz Bodies NationWide Laboratories |alt=|left]]
<u>'''Heinz bodies'''</u>. Oxidation of sulphydryl groups on the globin chains of haemoglobin results in the formation of Heinz bodies. These are refractile structures which occur along the internal surface of erythrocyte membranes, seen as pale pink-red projections with Romanowsky stains. Normal cats may have up to 5% Heinz bodies in their erythrocytes. Heinz body formation in the absence of anaemia may occur with feline diabetes mellitus, lymphoma and hyperthyroidism. Increased numbers of Heinz bodies, leading to haemolytic anaemia, may be associated with onion or garlic ingestion, kale or other brassica species consumption by ruminants and consumption of red maple leaves by alpacas and horses.
<u>'''Heinz bodies'''</u>. Oxidation of sulphydryl groups on the globin chains of haemoglobin results in the formation of Heinz bodies. These are refractile structures which occur along the internal surface of erythrocyte membranes, seen as pale pink-red projections with Romanowsky stains. Normal cats may have up to 5% Heinz bodies in their erythrocytes. Heinz body formation in the absence of anaemia may occur with feline diabetes mellitus, lymphoma and hyperthyroidism. Increased numbers of Heinz bodies, leading to haemolytic anaemia, may be associated with onion or garlic ingestion, kale or other brassica species consumption by ruminants and consumption of red maple leaves by alpacas and horses.
[[File:NWLLabfacts 6.jpg|thumb|Howell-Jolly bodies NationWide Laboratories]]
[[File:NWLLabfacts 6.jpg|thumb|Howell-Jolly bodies NationWide Laboratories|alt=|left]]
<u>'''Howell-Jolly bodies.'''</u> These are remnants of nuclear material . They are present in regenerative anaemias possibly due to inability of macrophages to fully remove the nuclei of maturing RBCs during accelerated production. If present without polychromasia, reduced macrophage function could be considered. They may be a common finding following splenectomy.
[[File:NWLLabfacts 7.jpg|thumb|Hypochromasia NationWide Laboratories]]
[[File:NWLLabfacts 7.jpg|thumb|Hypochromasia NationWide Laboratories|alt=]]
Rouleaux are prominent in blood smears from normal horses and some cats. Rouleaux are alsoseen in animals with hyperglobulinaemia, particularly h yperfibrinogenaemia and elevated acute phase proteins.
Rouleaux are prominent in blood smears from normal horses and some cats. Rouleaux are alsoseen in animals with hyperglobulinaemia, particularly h yperfibrinogenaemia and elevated acute phase proteins.
[[File:NWLLabfacts 10.jpg|thumb|Target Cells (codocytes) NationWide Laboratories]]
[[File:NWLLabfacts 10.jpg|thumb|Target Cells (codocytes) NationWide Laboratories|alt=|left]]
'''<u>Target cells (codocytes)</u>'''. These are bell-shaped in-vivo but resemble a target on a blood smear due to accumulation of haemoglobin around the periphery and centre.
'''<u>Target cells (codocytes)</u>'''. These are bell-shaped in-vivo but resemble a target on a blood smear due to accumulation of haemoglobin around the periphery and centre.
They may be encountered with regenerative anaemia, renal, hepatic or lipid disorders.
They may be encountered with regenerative anaemia, renal, hepatic or lipid disorders.
=== Inclusions ===
=== Inclusions ===
Hypochromasia (see image)
Hypochromasia (see image)
Red Cell fragmentation (see image)[[File:NWLLabfacts 11.jpg|thumb|Mycoplasma haemofelis NationWide Laboratories]]
Red Cell fragmentation (see image)[[File:NWLLabfacts 11.jpg|thumb|Mycoplasma haemofelis NationWide Laboratories|alt=|left]]
[[File:NWLLabfacts 12.jpg|thumb|Babesia Canis NationWide Laboratories]]
[[File:NWLLabfacts 12.jpg|thumb|Babesia Canis NationWide Laboratories]]
Leucocyte evaluation
Normal blood should contain mature leucocyte populations which fall within reference limits for the species under consideration. A blood smear should be examined for abnormal cells prior to performing the differential cell count.
Normal blood should contain mature leucocyte populations which fall within reference limits for the species under consideration. A blood smear should be examined for abnormal cells prior to performing the differential cell count.
[[File:NWLLabfacts 13.jpg|thumb|Neutrophil NationWide Laboratories]]
[[File:NWLLabfacts 13.jpg|thumb|Neutrophil NationWide Laboratories]]