Leukogram Flashcards
What is the difference between -penia and -philia/-cytosis?
decreased concentration of cells (neutropenia, lymphopenia, eosinopenia)
increased concentration of cells (neutrophilia, eosinophilia, basophilia, monocytosis, lymphocytosis)
What is left shift? What does it mean if it’s associated with neutropenia?
increased concentration of immature neutrophils in the blood, usually band neutrophils but can be metamyelocytes
more severe inflammatory response
What is orderly maturation? What does it mean if a left shift is orderly? Disorderly?
concentration of each cell increases with the degree of maturity
there should be more bands than metamyelocytes, and more segmented neutrophils than bands
consumption if very severe or a neoplastic process is present (leukemia)
What is leukemia?
presence of neoplastic cells in the blood or bone marrow with a variable concentration from non-detectable to >500,000 µL
What are lymphoproliferative and myeloproliferative disorders?
LYMPHOPROLIFERATIVE - neoplasms of lymphocytes and plasma cells
MYELOPROLIFERATIVE - neoplasms arising from bone marrow stem cells and involve neutrophils, monocytes, erythrocytes, and rarely eosinophils or basophils
How can analyzers record incorrect total WBC counts? What does this mean?
some analyzers count all nucleated cells as WBCs
- may need a correction factor if there are many nRBCs present
- manual counting by hemocytometer is required for avian/exotics because automated counting will not be reliable with their nRBCs
What are 2 common causes of false decreased WBCs? 3 causes of false increased WBCs?
FALSE DECREASED
1. leukocyte clumping
2. leukocyte lysis common with delayed analysis
FALSE INCREASED
1. abnormally large platelets or platelet clumps
2. high numbers of Heinz bodies
3. high numbers of nRBCs
What are 2 common causes of inaccuracy of WBC from blood smears?
- uneven cell distribution
- poor quality of smear preparation
What WBC information can be reported from automated hematology analyzers? Stained blood smear?
concentrations of each leukocyte type (% and absolute counts)
manual differential counts - a good way to confirm that the instrument is counting cells correctly and evaluate leukocyte morphology and presence of microorganisms
How are manual leukocyte differentials done?
- count 100 WBCs at 50-100x lens with oil
- categorize cells seen (segmented neutrophils, band neutrophils, lymphocytes, eosinophils)
- calculate the percent of each cell out of 100
this is just a % of leukocytes, NOT an absolute
How is the absolute lymphocyte count established?
multiply the % of each leukocyte by the total WBC count
33% lymphocytes, total WBC count - 26,000/µL
= 0.33 x 26,000/µL
= 8,580 µL absolute lymphocyte count
What count is used to interpret WBC results? Why?
ABSOLUTE COUNT, not % —> absolute counts have established reference intervals and are more accurate
WBC leukogram:
What are 3 causes of neutrophilia/heterophilia? What is also seen in these cases?
- PHYSIOLOGIC - lymphocytosis, no left shift
- CORTICOSTEROID-INDUCED (stress) - lymphopenia, no left shift
- INFLAMMATORY - left shift, neutrophil concentration >2x upper limit reference interval
What causes physiologic neutrophilia/heterophilia? What is most commnonly seen with this?
release of epinephrine from fear, excitement, or frisht causes mobilization of marginated neutrophil pools into the circulating neutrophil pool
concurrent lymphocytosis
What does the concurrent lymphocytosis in physiologic neutrophilia/heterophilia cause? In what animals is this most common?
lymphocytes are released from thoracic duct and stay in circulation
more prominent feature in feline excitement response, and seen in horses and cattle
What are 2 causes of stress/corticosteroid neutrophilia/heterophilia? What is most commonly seen with it?
- illness, pain, or metabolic disordered treated with corticosteroids
- corticosteroid-producing tumors
lymphopenia with lymphocytes sequestered in lymphoid tissue
What 2 things are additionally seen in stress/corticoid neutrophilia/heterophilia in dogs?
- eosinopenia
- monocytosis