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Preparation and Examination of Blood Smear (view source)
Revision as of 16:48, 15 March 2022
, 16:48, 15 March 2022no edit summary
Well prepared blood smears should have an area where the blood cells are in a monolayer. Place a small drop of blood on the slide towards one end. Draw the spreader slide back to contact the drop and then move it forwards before the blood has spread along the width of the spreader slide. This will prevent the smear extending to the extremities of the slide, when cells can be lost over the edges. The smear should terminate before the end of the slide (Fig 1).
Well prepared blood smears should have an area where the blood cells are in a monolayer. Place a small drop of blood on the slide towards one end. Draw the spreader slide back to contact the drop and then move it forwards before the blood has spread along the width of the spreader slide. This will prevent the smear extending to the extremities of the slide, when cells can be lost over the edges. The smear should terminate before the end of the slide (Fig 1).
The area to be examined is the monolayer where 50% or less of cells are in contact. The differential count is performed, and cell morphology is assessed in the monolayer (Fig 2).
The area to be examined is the monolayer where 50% or less of cells are in contact. The differential count is performed, and cell morphology is assessed in the monolayer (Fig 2).
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File:Nation Wide Laboratories.png
File:Nation Wide Laboratories.png| ©NationWide Laboratories 2017
File:NationWide Laboratories Fig2.png
File:NationWide Laboratories Fig2.png
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<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.
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File:NWL Labfacts .jpg|Stain precipitate NationWide Laboratories
File:NWL Labfacts .jpg|'''Stain precipitate''' ©NationWide Laboratories 2017
File:NWL Lab.jpg|Refractile bodies NationWide Laboratories
File:NWL Lab.jpg|'''Refractile bodies''' ©NationWide Laboratories 2017
File:NWLab .jpg|Echinocytes, a small and large platelet NationWide Laboratories|alt=
File:NWLab .jpg|'''Echinocytes, a small and large platelet''' ©NationWide Laboratories 2017
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<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.
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File:NWL 2016 Labfacts inners A.jpg|Anisocytosis and Polychromasia NationWide Laboratories
File:NWL 2016 Labfacts inners A.jpg|'''Anisocytosis and Polychromasia''' ©NationWide Laboratories 2017
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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.
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<br/><u>'''Reticulocytes'''</u>. Immature red cells, their residual RNA and mitochondria stain with new methylene blue.
<u>'''Reticulocytes'''</u>. Immature red cells, their residual RNA and mitochondria stain with new methylene blue.
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File:NWL 2016.jpg|'''Canine reticulocytes''' ©NationWide Laboratories 2017
File:NWL 2016.jpg|Canine reticulocytes NationWide Laboratories|alt=
File:NW laboratories.jpg|'''Feline Reticulocytes''' ©NationWide Laboratories 2017
File:NW laboratories.jpg|Feline Reticulocytes NationWide Laboratories
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<u>'''Nucleated red blood cells (metarubricytes)'''.</u> These are immature red cells, which retain a condensed nucleus.
<u>'''Nucleated red blood cells (metarubricytes)'''.</u> These are immature red cells, which retain a condensed nucleus.
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File:NationWide Lab 2016.jpg|Nucleated red blood cell NationWide Laboratories
File:NationWide Lab 2016.jpg|'''Nucleated red blood cell''' ©NationWide Laboratories 2017
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=== Immune mediated haemolytic anaemia (IMHA) ===
=== Immune mediated haemolytic anaemia (IMHA) ===
<u>'''Agglutination'''.</u> This describes the random, three dimensional clumping of red cells. Autoagglutination is persistent agglutination, which cannot be dispersed in saline. It is pathognomonic for IMHA but is not seen in all cases. Autoagglutination will affect red cell indices in automated analysers (increased MCV, MCH and MCHC).
<u>'''Agglutination'''.</u> This describes the random, three dimensional clumping of red cells. Autoagglutination is persistent agglutination, which cannot be dispersed in saline. It is pathognomonic for IMHA but is not seen in all cases. Autoagglutination will affect red cell indices in automated analysers (increased MCV, MCH and MCHC).
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File:NWLLabfacts 1.jpg|Autoagglutination NationWide Laboratories
File:NWLLabfacts 1.jpg|'''Autoagglutination''' ©NationWide Laboratories 2017
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<u>'''Spherocytes''':</u> These are spherical erythrocytes which appear smaller in diameter, stain more densely and lack central pallor. They are more obvious in canine blood (feline erythrocytes naturally lack central pallor) and are most commonly associated with IMHA. Other causes include snake bite, zinc toxicity and bee stings.
<u>'''Spherocytes''':</u> These are spherical erythrocytes which appear smaller in diameter, stain more densely and lack central pallor. They are more obvious in canine blood (feline erythrocytes naturally lack central pallor) and are most commonly associated with IMHA. Other causes include snake bite, zinc toxicity and bee stings.
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File:NWLLabfacts 2.jpg|Spherocytes with central polychromatophil NationWide Laboratories
File:NWLLabfacts 2.jpg|'''Spherocytes with central polychromatophil''' ©NationWide Laboratories 2017
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=== Other morphological changes ===
=== Other morphological changes ===
<u>'''Acanthocytes'''</u>. Erythrocytes with a few irregular, asymmetrical projections. In dogs acanthocytes may be associated with haemangiosarcoma, lymphoma, DIC and altered lipid metabolism (hepatic disease). In cats they may be recognised with liver disease including the cholangitis complex and hepatic lipidosis.
<u>'''Acanthocytes'''</u>. Erythrocytes with a few irregular, asymmetrical projections. In dogs acanthocytes may be associated with haemangiosarcoma, lymphoma, DIC and altered lipid metabolism (hepatic disease). In cats they may be recognised with liver disease including the cholangitis complex and hepatic lipidosis.
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File:NWLLabfacts 3.jpg|Acanthocytes NationWide Laboratories
File:NWLLabfacts 3.jpg|'''Acanthocytes''' ©NationWide Laboratories 2017
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<u>'''Basophilic stippling'''.</u> Reflects the presence of aggregated ribosomal RNA in reticulocytes and is primarily associated with regenerative anaemias. It is also evident with the exaggerated regenerative response seen in many cases of lead poisoning (often in the absence of anaemia), due to the effect of lead on the bone marrow.
<u>'''Basophilic stippling'''.</u> Reflects the presence of aggregated ribosomal RNA in reticulocytes and is primarily associated with regenerative anaemias. It is also evident with the exaggerated regenerative response seen in many cases of lead poisoning (often in the absence of anaemia), due to the effect of lead on the bone marrow.
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File:NWLLabfacts 4.jpg|Basophilic stippling NationWide Laboratories
File:NWLLabfacts 4.jpg|'''Basophilic stippling''' ©NationWide Laboratories 2017
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<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.
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File:NWLLabfacts 5.jpg|Heinz Bodies NationWide Laboratories |alt=
File:NWLLabfacts 5.jpg|'''Heinz Bodies''' ©NationWide Laboratories 2017
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<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.
<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.
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File:NWLLabfacts 6.jpg|Howell-Jolly bodies NationWide Laboratories|alt=
File:NWLLabfacts 6.jpg|'''Howell-Jolly bodies''' ©NationWide Laboratories 2017
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'''<u>Red cell fragmentation.</u>''' Small fragments are called schistocytes (schizocytes), larger red cell fragments include keratocytes (blister and helmet cells). These reflect metabolic disease or, more commonly, intravascular trauma associated with turbulent blood flow due to cardiac valvular disease, with passage through numerous capillaries in haemangiosarcoma and certain other malignant neoplasms, or fibrin strands cleaving erythrocytes in myelofibrosis or DIC. Severe hepatic disease may also result in red cell fragmentation.
'''<u>Red cell fragmentation.</u>''' Small fragments are called schistocytes (schizocytes), larger red cell fragments include keratocytes (blister and helmet cells). These reflect metabolic disease or, more commonly, intravascular trauma associated with turbulent blood flow due to cardiac valvular disease, with passage through numerous capillaries in haemangiosarcoma and certain other malignant neoplasms, or fibrin strands cleaving erythrocytes in myelofibrosis or DIC. Severe hepatic disease may also result in red cell fragmentation.
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File:NWLLabfacts 8.jpg|Red Cell fragmentation NationWide Laboratories
File:NWLLabfacts 8.jpg|'''Red Cell fragmentation''' ©NationWide Laboratories 2017
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'''<u>Rouleaux.</u>''' These are stacks of erythrocytes resembling a pile of coins, which disperse in saline. Rouleaux are most obvious when examining the body of the blood smear.
'''<u>Rouleaux.</u>''' These are stacks of erythrocytes resembling a pile of coins, which disperse in saline. Rouleaux are most obvious when examining the body of the blood smear.
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.
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File:NWLLabfacts 9.jpg|Rouleaux in an equine blood smear NationWide Laboratories
File:NWLLabfacts 9.jpg|'''Rouleaux in an equine blood smear''' ©NationWide Laboratories 2017
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'''<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.
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File:NWLLabfacts 10.jpg|Target Cells (codocytes) NationWide Laboratories|alt=
File:NWLLabfacts 10.jpg|'''Target Cells (codocytes)''' ©NationWide Laboratories 2017
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=== Inclusions ===
=== Inclusions ===
Mycoplasma haemofelis (see image)
Mycoplasma haemofelis (see image)
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File:NWLLabfacts 11.jpg|Mycoplasma haemofelis NationWide Laboratories|alt=
File:NWLLabfacts 11.jpg|'''Mycoplasma haemofelis''' ©NationWide Laboratories 2017
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Babesia canis (see image)
Babesia canis (see image)
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File:NWLLabfacts 12.jpg|Babesia Canis NationWide Laboratories
File:NWLLabfacts 12.jpg|'''Babesia Canis''' ©NationWide Laboratories 2017
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'''<u>Neutrophil.</u>''' A mature neutrophil has a segmented nucleus with condensed chromatin and fine intracytoplasmic azurophilic granules.
'''<u>Neutrophil.</u>''' A mature neutrophil has a segmented nucleus with condensed chromatin and fine intracytoplasmic azurophilic granules.
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File:NWLLabfacts 13.jpg|Neutrophil NationWide Laboratories
File:NWLLabfacts 13.jpg|'''Neutrophil''' ©NationWide Laboratories 2017
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In females, the nucleus may have a drum-stick shaped appendage known as a Barr body which represents the inactive X chromosome; this is of no clinical significance.
In females, the nucleus may have a drum-stick shaped appendage known as a Barr body which represents the inactive X chromosome; this is of no clinical significance.
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File:NWLLabfacts 14.jpg|Barr body NationWide Laboratories
File:NWLLabfacts 14.jpg|'''Barr body''' ©NationWide Laboratories 2017
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'''<u>Band neutrophil.</u>''' This is an immature cell with an unsegmented nucleus showing parallel sides.The cytoplasm is similar to that of a mature cell.
'''<u>Band neutrophil.</u>''' This is an immature cell with an unsegmented nucleus showing parallel sides.The cytoplasm is similar to that of a mature cell.
Sometimes less differentiated myeloid cells (metamyelocytes and myelocytes) are seen in the blood, usually associated with a severe acute inflammatory response. This is called a left shift.
Sometimes less differentiated myeloid cells (metamyelocytes and myelocytes) are seen in the blood, usually associated with a severe acute inflammatory response. This is called a left shift.
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File:NWLLabfacts 16.jpg|Metamyelocyte NationWide Laboratories
File:NWLLabfacts 16.jpg|'''Metamyelocyte''' ©NationWide Laboratories 2017
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'''<u>Toxic neutrophil.</u>''' Toxic change describes the leucocyte morphological abnormalities, seen predominantly in neutrophils, in the face of severe inflammation. The cytoplasm may show increased basophilia (light blue or grey rather than pink) and may contain Dohle bodies, which are small round or angular blue inclusions representing retained RNA (normally degraded during maturation). Dohle bodies are often seen in feline neutrophils and are not clinically significant unless frequent and prominent.
'''<u>Toxic neutrophil.</u>''' Toxic change describes the leucocyte morphological abnormalities, seen predominantly in neutrophils, in the face of severe inflammation. The cytoplasm may show increased basophilia (light blue or grey rather than pink) and may contain Dohle bodies, which are small round or angular blue inclusions representing retained RNA (normally degraded during maturation). Dohle bodies are often seen in feline neutrophils and are not clinically significant unless frequent and prominent.
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File:NWLLabfacts 17.jpg|Dohle bodies in the cytoplasm of a neutrophil NationWide Laboratories
File:NWLLabfacts 17.jpg|'''Dohle bodies in the cytoplasm of a neutrophil''' ©NationWide Laboratories 2017
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Neutrophils may have swollen nuclei which sometimes form doughnuts.
Neutrophils may have swollen nuclei which sometimes form doughnuts.
Toxic change occurs in the bone marrow and reflects accelerated granulopoiesis, especiallyassociated with bacterial infections and IMHA.
Toxic change occurs in the bone marrow and reflects accelerated granulopoiesis, especiallyassociated with bacterial infections and IMHA.
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File:NWLLabfacts 18.jpg|thumb|Neutrophil with toxic granulation NationWide Laboratories
File:NWLLabfacts 18.jpg|'''Neutrophil with toxic granulation''' ©NationWide Laboratories 2017
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There may be toxic granulation due to staining of primary granules.
There may be toxic granulation due to staining of primary granules.
In severe toxaemia, neutrophils may show cytoplasmic vacuolation due to degranulation of lysosomes during disturbed maturation.
In severe toxaemia, neutrophils may show cytoplasmic vacuolation due to degranulation of lysosomes during disturbed maturation.
'''<u>Hypersegmented neutrophil.</u>''' There are more than 5 nuclear lobes. Found in dogs on corticosteroid therapy (which prolongs the half life of the neutrophil) and may be associated with uraemia. Also seen in Poodles with familial macrocytosis.
'''<u>Hypersegmented neutrophil.</u>''' There are more than 5 nuclear lobes. Found in dogs on corticosteroid therapy (which prolongs the half life of the neutrophil) and may be associated with uraemia. Also seen in Poodles with familial macrocytosis.
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File:NWLLabfacts 19.jpg|'''Hypersegmented neutrophil''' ©NationWide Laboratories 2017
File:NWLLabfacts 19.jpg|Hypersegmented neutrophil NationWide Laboratories
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'''<u>Eosinophil.</u>''' Mature eosinophils have a segmented nucleus and red intracytoplasmic granules. The granules in the dog are round and vary in size. In the cat they are small, uniform in size and rod shaped while in the horse the granules are round and very large. In rabbits, eosinophils have larger red granules than neutrophils although often the two cell types are difficult to differentiate and may be counted together as heterophils. Band eosinophils are immature cells showing less distinct nuclear segmentation.
'''<u>Eosinophil.</u>''' Mature eosinophils have a segmented nucleus and red intracytoplasmic granules. The granules in the dog are round and vary in size. In the cat they are small, uniform in size and rod shaped while in the horse the granules are round and very large. In rabbits, eosinophils have larger red granules than neutrophils although often the two cell types are difficult to differentiate and may be counted together as heterophils. Band eosinophils are immature cells showing less distinct nuclear segmentation.
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File:NWLLabfacts 20.jpg|Equine eosinophil NationWide Laboratories
File:NWLLabfacts 20.jpg|'''Equine eosinophil''' ©NationWide Laboratories 2017
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'''<u>Basophil.</u>''' Rare in blood smears from healthy animals. Basophils are similar in size to eosinophils, with a segmented, ribbon-like nucleus and variable numbers of cytoplasmic granules. In dogs these are deep purple and sparse. Cats have more numerous lilac coloured granules with occasional deep purple granules.
'''<u>Basophil.</u>''' Rare in blood smears from healthy animals. Basophils are similar in size to eosinophils, with a segmented, ribbon-like nucleus and variable numbers of cytoplasmic granules. In dogs these are deep purple and sparse. Cats have more numerous lilac coloured granules with occasional deep purple granules.
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File:NWLLabfacts 21.jpg|Basophil NationWide Laboratories
File:NWLLabfacts 21.jpg|'''Basophil''' ©NationWide Laboratories 2017
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'''<u>Mast cell.</u>''' These are not present in the blood of healthy animals but may be present with severe inflammatory disease or metastatic mast cell tumours (mastocytaemia). They are round cells with a round nucleus surrounded by a moderate volume of cytoplasm containing large numbers of purple granules.
'''<u>Mast cell.</u>''' These are not present in the blood of healthy animals but may be present with severe inflammatory disease or metastatic mast cell tumours (mastocytaemia). They are round cells with a round nucleus surrounded by a moderate volume of cytoplasm containing large numbers of purple granules.
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File:NWLLabfacts 22.jpg|Mast cell NationWide Laboratories
File:NWLLabfacts 22.jpg|'''Mast cell''' ©NationWide Laboratories 2017
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'''<u>Reactive lymphocyte.</u>''' Slightly larger than a mature lymphocyte. Cells have round nuclei with condensed nuclear chromatin, surrounded by a rim of pale basophilic cytoplasm.
'''<u>Reactive lymphocyte.</u>''' Slightly larger than a mature lymphocyte. Cells have round nuclei with condensed nuclear chromatin, surrounded by a rim of pale basophilic cytoplasm.
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File:NWLLabfacts 23.jpg|Small, medium and large Lymphocytes NationWide Laboratories
File:NWLLabfacts 23.jpg|'''Small, medium and large''' '''Lymphocytes''' ©NationWide Laboratories 2017
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<u>'''Lymphoblast.'''</u> A large cell with a large nucleus, two to three red cell widths in diameter, with one or more prominent nucleoli. These are rarely seen in blood smears from healthy animals but may be present with lymphoid neoplasia.
<u>'''Lymphoblast.'''</u> A large cell with a large nucleus, two to three red cell widths in diameter, with one or more prominent nucleoli. These are rarely seen in blood smears from healthy animals but may be present with lymphoid neoplasia.
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File:NWLLabfacts 24.jpg|Lymphoblast NationWide Laboratories
File:NWLLabfacts 24.jpg|'''Lymphoblast''' ©NationWide Laboratories 2017
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'''<u>Large granular lymphocyte</u>'''. Lymphocyte containing several prominent magenta coloured cytoplasmic granules. Rarely seen in peripheral blood but are numerous in large granular cell leukaemia in the dog
'''<u>Large granular lymphocyte</u>'''. Lymphocyte containing several prominent magenta coloured cytoplasmic granules. Rarely seen in peripheral blood but are numerous in large granular cell leukaemia in the dog
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File:NWLLabfacts 25.jpg|Large granular Lymphocyte NationWide Laboratories
File:NWLLabfacts 25.jpg|'''Large granular Lymphocyte''' ©NationWide Laboratories 2017
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<u>'''Monocyte'''</u>. These are large cells with a deeply indented nucleus showing pale, finely granular nuclear chromatin. They have a moderate amount of blue-grey cytoplasm, which may contain vacuoles.
<u>'''Monocyte'''</u>. These are large cells with a deeply indented nucleus showing pale, finely granular nuclear chromatin. They have a moderate amount of blue-grey cytoplasm, which may contain vacuoles.
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File:NWLLabfacts 26.jpg|Monocyte NationWide Laboratories
File:NWLLabfacts 26.jpg|'''Monocyte''' ©NationWide Laboratories 2017
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Canine distemper intracytoplasmic inclusion in a neutrophil (See image)
Canine distemper intracytoplasmic inclusion in a neutrophil (See image)
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File:NWLLabfacts 27.jpg|Canine distemper intracytoplasmic inclusion in a neutrophil NationWide Laboratories
File:NWLLabfacts 27.jpg|'''Canine distemper intracytoplasmic inclusion in a neutrophil''' ©NationWide Laboratories 2017
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Ehrlichia canis morula in a monocyte (see image)
Ehrlichia canis morula in a monocyte (see image)
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File:NWL 1.jpg|Ehrlichia canis morula in a monocyte NationWide Laboratories
File:NWL 1.jpg|'''Ehrlichia canis morula in a monocyte''' ©NationWide Laboratories 2017
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Leishmania in the cytoplasm of a neutrophil (see image)
Leishmania in the cytoplasm of a neutrophil (see image)
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File:NWL 2.jpg|Leishmania in the cytoplasm of neutrophil NationWide Laboratories
File:NWL 2.jpg|'''Leishmania in the cytoplasm of neutrophil''' ©NationWide Laboratories 2017
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Anaplasma platys elementary bodies (see image)
Anaplasma platys elementary bodies (see image)
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File:NWL 3.jpg|Anaplasma platys elementary bodies NationWide Laboratories
File:NWL 3.jpg|'''Anaplasma platys elementary bodies''' ©NationWide Laboratories 2017
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Hepatozoon gametocytes and Ehrlichia Morula (see image)
Hepatozoon gametocytes and Ehrlichia Morula (see image)
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File:NWL 4.jpg|Hepatozoon gametocytes and Ehrlichia Morula NationWide Laboratories
File:NWL 4.jpg|'''Hepatozoon gametocytes and Ehrlichia Morula''' ©NationWide Laboratories 2017
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Platelet numbers can be estimated from the blood smear as described previously. The smear should be checked for any platelet clumps which are often found in the tail (feathered edge) of the smear. Clumping of platelets is frequently seen in cats and results in a spuriously low platelet count.
Platelet numbers can be estimated from the blood smear as described previously. The smear should be checked for any platelet clumps which are often found in the tail (feathered edge) of the smear. Clumping of platelets is frequently seen in cats and results in a spuriously low platelet count.
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File:NWL 5.jpg|Clumps of platelets, often found in the feathered edge NationWide Laboratories
File:NWL 5.jpg|'''Clumps of platelets, often found in the feathered edge''' ©NationWide Laboratories 2017
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'''<u>Macrothrombocyte.</u>''' A large platelet indicating enhanced thrombopoiesis. Larger platelets are more functionally active and this may explain why some dogs with thrombocytopaenia, but largeplatelets, do not bleed.
'''<u>Macrothrombocyte.</u>''' A large platelet indicating enhanced thrombopoiesis. Larger platelets are more functionally active and this may explain why some dogs with thrombocytopaenia, but largeplatelets, do not bleed.
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File:NWL 6.jpg|Macrothrombocyte Nation Wide Laboratories (the one in the middle)
File:NWL 6.jpg|'''Macrothrombocyte Nation Wide Laboratories''' (the one in the middle) ©NationWide Laboratories 2017
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Primary platelet disorders such as thrombasthenic thrombopathia of otter hounds are rare, producing large and morphologically bizarre platelets. Cavalier King Charles spaniels may have large platelets with decreased platelet counts due to inherited macrothrombocytopaenia.
Primary platelet disorders such as thrombasthenic thrombopathia of otter hounds are rare, producing large and morphologically bizarre platelets. Cavalier King Charles spaniels may have large platelets with decreased platelet counts due to inherited macrothrombocytopaenia.
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File:NWL 7.jpg|Inherited macrothrombocytopaenia NationWide Laboratories
File:NWL 7.jpg|'''Inherited macrothrombocytopaenia''' ©NationWide Laboratories 2017
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