Blood smears

Question 1

How can you assess for analytical errors?

Answer 1

Quality control
Plausibility evaluation
Techincal and medical review
method of obtaining results from a sample

Question 2

What can excitement (epinephrine) do to a haematology sample?

Answer 2

Lymphocytosis

Question 3

Are band cells part of a stress leukogram?

Answer 3

No

Question 4

What makes a good blood smear?

Answer 4

3/4 length of the slide
Well defined monolayer
Well defined feathered edge
No holes

WBCs not at feathered edge
Evenly distributed WBCs/ platelets
Well stained with good contrast and colour
No stain precipitate or other artifacts

Question 5

What can a moderate to marked leukocytosis affect on haematology?

Answer 5

Hb
Platelet count
MCV

Question 6

What can a microcytosis do to a haematology results

Answer 6

May cause errors in RBC, platelet numbers, and MCV, as they are confused for platelets

Question 7

What can a lipaemia/ chylomicrons do to a haematology sample?

Answer 7

Cause errors in WBCs, platelets and eosinophils due to an affect on the light reflection that the measurements use

Question 8

How do you do a WBC measurement on a smear?

Answer 8

Average WBCs per 40 field x 2000

Question 9

How do you do a platelet measurement on a smear and how do values suggest the levels are?

Answer 9

Average per 100x field x 20,000

<2 per hpf - v low
2-5 low
5-25 adequate
25-50 high
>50 v high

Question 10

How do you differentiate between band and segmented neutrophils?

Answer 10

bands have parrallel sides

Segmented when any indentation of the nucleus is >25% of the nucleus

Question 11

What is the rule of thumb with reticulocytes and polychromatophils

Answer 11

All polychromatophils are reticulocytes, but not all reticulocytes are polychromatophils

Question 12

Which stain is good for parasites?

Answer 12

new methylene blue

Question 13

What is the rule of 3 for checking if results are plausible?

Answer 13

Hct +/-3 = Hb x 3

Question 14

What should you do if MCHC is high

Answer 14

Not physiologically possible

Look for signs of haemolysis

Question 15

What are Howell-Jolly bodies?

Answer 15

small but prominent dark inclusions which are remnants of nuclear material
Sign of regeneration

Question 16

What does babesia look like in blood?

Answer 16

Babesia canis appear as large pear-shaped organisms, usually in pairs
B. gibsoni organisms are much smaller, circular bodies. These parasites are more often seen in capillary blood (e.g. from an ear prick) and most frequently found along the edges of films. However, these
organisms are not always visualized and
serology or PCR are more sensitive

Question 17

What does feline infectious anaemia look like in blood?

Answer 17

Provided that samples are obtained during an episode of parasitaemia, organisms may be identified using the Rowmanowsky stains.
The organisms stain blue–grey to pale purple with Rowmanowsky stains and appear as small cocci singly or in chains. Again PCR is a more sensitive diagnostic technique.

Question 18

Outline how does oxidant injury appear in blood?

Answer 18

Ingestion of oxidants such as onions or zinc can lead to the formation of Heinz bodies or eccentrocytes with resultant anaemia.
Heinz bodies are seen as non-staining round bodies, usually protruding from the surface of the cell. Eccentrocytes have a pale area on one side of the cell which is devoid of haemoglobin, but with a cell
membrane visible around this pale area

Question 19

How does microangiopathic anaemia appear?

Answer 19

Red blood cell fragmentation, e.g. due to
vascular neoplasms such as haemangiosarcoma, results in the formation of schistocytes and acanthocytes.
Schistocytes are irregular-shaped, often with elongated fragments and an irregular spiked outline. Acanthocytes also have irregular spiky projections but are roundish in shape.

Question 20

What does iron deficiency anaemia look like?

Answer 20

This leads to defective haemoglobin
synthesis, and so red blood cells are very
pale with a wide area of central pallor and a
thin rim of haemoglobin

Question 21

What are some signs of toxic change in neutrophils?

seen in bacterial infection/ severe inflammation

Answer 21

Döhle bodies – indistinct blue–grey
cytoplasmic inclusions
Increased cytoplasmic basophilia (but not as dark as monocytes) 
Foamy vacuolated cytoplasm
Cytoplasmic granules 
Giant neutrophils
Nuclear swelling
Doughnut-shaped nuclei.

Question 22

What are the possible causes for lymphocytosis?

Answer 22

chronic infection or inflammation,
lymphocytic leukemia,
physiologic lymphocytosis

Question 23

What do glucocorticoids do to a haematology?

Answer 23

mature neutrophilia by increasing release of mature neutrophils from the marrow storage pool, demarginating neutrophils from the marginal neutrophil pool (MNP) into the circulating neutrophil pool (CNP), and decreasing neutrophil migration into tissues.

Question 24

What may lead poisoning show in a smear?

Answer 24

Basophilic stippling

Question 25

What are causes of a v mild anaemia that has a marked metarubircyte componenet?

Answer 25

This is a nonregenerative anemia because the response is disordered and causes of inappropriate metarubricytosis should be pursued. These include marrow neoplasia, myelofibrosis, lead poisoning, myelophthisis, extramedullary hematopoiesis, or severe anoxia

Question 26

What would a normal regenerative response to blood loss look like?

Answer 26

macrocytic and hypochromic

if the animal became really anaemic then it could appear microcytic hypochromic

Question 27

What is a degenerative left shift

Answer 27

bands exceed mature neutrophils with a normal WBC count. Indicates a poor prognosis

Question 28

What can cause marked eosinophilia?

Answer 28

allergy and hypersensitivity reactions, chronic granulomatous disease, and neoplasms such as mast cell tumors or lymphoma.
Eosinophilic leukemia and hypereosinophilic syndrome are infrequent causes

Question 29

Does erythropoietin stimulate platelet production?

Answer 29

Yes

Question 30

How long do RBCs last?

Answer 30

100d dog

80-90 cats

Question 31

How is crenation affected by storage?

Answer 31

Crenation is more prominent in films made from EDTA-antico agulated blood than in films made from fresh non-anticoagulated blood.

Question 32

What occurs in maturation defect anaemias?

Answer 32

Maturation defect anemias have nonregenerative peripheral blood patterns but erythroid hyperplasia in the bone marrow.

Question 33

What are the lab features of relative polycythaemia?

Answer 33

A. Moderate increases in PCV

B. Elevated total protein concentration

C. Hypernatremia and hyperchloremia

D. Concentrated urine specific gravity

Question 34

Outline neutrophils

Answer 34

A. Neutrophils serve as the primary defense against invasion of tissues by microorganisms.

B. Neutrophils kill bacteria and can also damage or participate in the destruction of mycotic agents, algae, and viruses.

C. Neutrophils accumulate at sites of inflammation or bacterial infection by a process of directional migration or chemotaxis.

D. At the site of inflammation, neutrophils are capable of phagocytosis and microbicidal activity.

Question 35

What are the functions of macrophages?

Answer 35

A. Phagocytosis

B. Regulation of the inflammatory response via release of inflammatory mediators

C. Antigen-processing for presentation to lymphocytes

D. Regulation of body iron stores

Question 36

What can monocytosis suggesr?

Answer 36

A. The presence of inflammation

B. Demand for phagocytosis

C. Tissue necrosis

D. A “stress response” induced by high circulating glucocorticoids

Question 37

What is the most reliable componenet of a stress leukogram?

Answer 37

Lymphocyte counts between 750/ul and 1500/ul