Cross Species - White Blood Cell Parameters

Question 1

what cells are granulocytes?

Answer 1

neutrophils, eosinophils, & basophils

Question 2

what cells are mononuclear cells?

Answer 2

lymphocytes & monocytes

Question 3

what is the half life of neutrophils? how long does production in the bone marrow take?

Answer 3

first defense against bacterial pathogens - 10-15 hours & production takes 3-5 days

Question 4

what is margination in regards to neutrophils?

Answer 4

adhesion to the blood vessel endothelium - these aren’t counted on the CBC

Question 5

what is the ratio of marginated to circulating neutrophils? what about in cats?

Answer 5

1:1, exception in cats is 2-3:1

Question 6

T/F: normally, only mature/segmented neutrophils are in circulation

Answer 6

TRUE

Question 7

endogenous/exogenous glucocorticoids & epinephrine in cats & horses cause what to happen to the neutrophils?

Answer 7

release of marginated pool & rapid increase in circulating neutrophils - main component of stress/physiologic leukogram

Question 8

what are the 2 main causes of an increased neutrophil count on a CBC?

Answer 8

any source of inflammation/infection causing a release of neutrophils from the bone marrow storage pool & glucocorticoid/epinephrine response with a release of marginated neutrophils

Question 9

what are the 4 main causes of a decreased neutrophil count on a CBC?

Answer 9

viral infections, inflammation/infection with increased tissue migration (migration most common), bone marrow disease (toxicity, leukemia, & aplasia), & chemotherapy administration

Question 10

what are the characteristics of a left shift?

Answer 10

increase in number of immature neutrophils - often concurrent with toxic change due to an increase in production in the bone marrow & premature release secondary to more significant inflammation/infection

Question 11

what is a band neutrophil?

Answer 11

immature neutrophil - lack of nuclear segmentation

Question 12

what is a degenerative left shift?

Answer 12

more bands than mature neutrophils in circulation - from severe infection/inflammation (bacterial sepsis in foals or endotoxemia in adult horses)

Question 13

what is the typical appearance of an eosinophil?

Answer 13

pink/orange staining cytoplasmic granules

Question 14

what are some causes of eosinophilia?

Answer 14

type I hypersensitivity reaction, parasitism, mast cell tumors, hypoadrenocorticism, & idiopathic in rottweiler’s/cats

Question 15

what is the main cause of eosinopenia?

Answer 15

stress leukogram

Question 16

T/F: low numbers of basophils are seen in healthy cow/horse blood & are rarely seen in healthy dogs/cats

Answer 16

TRUE

Question 17

what is the most numerous circulating WBC in cattle & rodents?

Answer 17

lymphocytes

Question 18

where are lymphocytes produced?

Answer 18

lymph tissue - lymph nodes, spleen!!! not bone marrow!!!

Question 19

T/F: lymphocytes are the smallest leukocyte

Answer 19

TRUE

Question 20

T/F: lymphocytes can exist in circulation for days to weeks

Answer 20

TRUE

Question 21

what other cells may look like lymphocytes on a CBC?

Answer 21

nRBC, neoplastic cells (myeloid or lymphoid leukemia)

Question 22

what are some causes of lymphocytosis?

Answer 22

antigenic stimulation, physiologic response to epinephrine in stressed cats, horses, & some dogs, animals under 6 months old, bovine leukosis, exercise-related in horses, addison’s, & chronic lymphocytic leukemia (dogs & cats)

Question 23

what is the main cause of a lymphopenia?

Answer 23

response to glucocorticoids (stress leukogram)

Question 24

when are reactive lymphocytes seen? how do you differentiate them from lymphoblasts?

Answer 24

immune response - they are deeper blue with more cytoplasm +/- clear cytoplasmic vacuoles - you will only see blasts with hematopoietic neoplasia (acute leukemia & lymphoma)

Question 25

T/F: blood monocytes are identical to tissue macrophages

Answer 25

TRUE

Question 26

what are some causes of a monocytosis?

Answer 26

chronic inflammatory/infectious disease & respone to glucocorticoids (stress leukogram)

Question 27

what do mast cells look like?

Answer 27

round, eccentric nucleus that typically stains liighter than dark purple cytoplasmic granules

Question 28

when may mast cells be seen in the blood?

Answer 28

type I hypersensitivty, severe inflammation, lymphoma, & mast cell tumors

Question 29

what is the common pattern of a stress leukogram?

Answer 29

due to cortisol - mature neutrophilia, lymphopenia, monocytosis (uncommon in catsm horses, & cattle), & an eosinopenia

Question 30

what is the common pattern of a physiologic leukogram?

Answer 30

due to epinephrine in horses & cats - mature neutrophilia & lymphocytosis

Question 31

T/F: a CBC can be normal with inflammatory/infectious/immune-mediated disease

Answer 31

TRUE

Question 32

what is the common pattern of an inflammatory leukogram?

Answer 32

neutrophilia +/- left shift, +/- toxic change, +/- monocytosis/lymphopenia/eosinopenia

Question 33

why do you always need to do a manual platelet count?

Answer 33

platelet clumping is normal & can significantly decrease the automated count

Question 34

how do you perform a manual platelet estimation?

Answer 34

evaluate on 100x field, count platelets in 10 fields & average, average platelet count X 15,000 = estimated count

Question 35

what are the normal platelet counts of dogs, cats, horses, & ruminants?

Answer 35

dogs & cats: greater than 200,000, horses: greater than 100,000, & ruminants: greater than 400,000

Question 36

spontaneous bleeding can occur if platelets get below what level?

Answer 36

30,000

Question 37

what is a primary cause of thrombocytosis?

Answer 37

myeloproliferative disease

Question 38

what is a secondary cause of thrombocytosis?

Answer 38

neoplasia, immune-mediated disease, & chronic inflammatory disease

Question 39

what is the most common cause of decreased platelets in dogs?

Answer 39

IMTP

Question 40

what are some causes of thrombocytopenia in dogs?

Answer 40

decreased bone marrow production, increased consumption (DIC), sequestration in spleen/microvasculature, & increased detruction (IMTP)

Question 41

what does an increase in MPV indicate?

Answer 41

regenerative response

Question 42

what causes spurious thrombocytopenia?

Answer 42

platelet clumping