76 Questions
What is the purpose of performing a differential count?
To classify the cells into different types based on their characteristics
How are quantities of cells expressed when performing a differential count?
In absolute values
Which WBC type is characterized by relatively bluish and denser staining cytoplasm compared to neutrophils?
Eosinophils
What is the significance of calculating absolute values in interpreting differential count results?
To infer the relative number of different cell types accurately
Which WBC is often described as having chromatin that is streaky, diffuse, or mesh-like?
Monocytes
What should be done with broken or smudge cells when performing a differential count?
Ignore them
Which type of leukocyte is the most abundant in the first case?
Neutrophil
What is the function of basophils in the body?
Allergic responses
In the second case, what is the absolute count of lymphocytes?
6240
What is the mature form of a band neutrophil?
Segmented neutrophil
What is the classification of eosinophils based on their staining properties?
Acidophils
During a differential count, what is being identified?
Relative proportion of each WBC type
Which type of leukocyte is primarily responsible for phagocytosis?
Neutrophils
At what stage of maturation are eosinophils recognizable?
Myelocyte stage
What is the function of basophils in the body?
Inhibition of allergic reactions
Which leukocyte type has granules that stain red with eosin and functions in allergic reactions?
Basophils
How do neutrophils in patients with bacterial infections typically differ from mature neutrophils?
More irregular lobes
Which leukocyte type has a nucleus that can be partially obscured by its granules?
Eosinophils
When do granules begin to form in the cytoplasm of developing leukocytes?
At the progranulocyte stage
Which leukocyte type has a nucleus that changes from round to segmented as it matures?
Neutrophils
What is the primary function of neutrophils in the body?
Phagocytosis
Which feature is characteristic of band neutrophils found in the blood?
Smooth nuclear membrane
What distinguishes hypersegmented neutrophils from normal segmented neutrophils?
Having more than 5 nuclear lobes
Which leukocyte type is characterized by an irregular and elongated nucleus with true filaments between lobes?
Neutrophils
During a differential count, what is primarily identified?
Different types of white blood cells
What is the main distinguishing feature between immature and mature granulocytes?
Nuclear segmentation
Which leukocyte type has granules that stain red with eosin and functions in allergic reactions?
Eosinophils
What is the chromatin appendage called that is visible in some neutrophils of female individuals?
Drumstick chromatin
What is the predominant stain that eosinophils have a strong affinity for?
Eosin
Which animal species has eosinophils with granules that vary in size from small to large and can show vacuoles?
Horses
What is the function of eosinophils within the immune system?
Mediation of the immune response
Which leukocyte type has nuclei that resemble those of monocytes, with granules that stain purple to blue-black?
Basophils
What does an increased number of basophils in circulation often indicate?
Allergic reaction
Which type of leukocyte is specific to the immune system and can differentiate into plasma cells?
Lymphocytes
What characterizes the cytoplasm of medium to large lymphocytes?
"Ground glass" appearance
What is the purpose of calculating the absolute value of different cell types in a total white blood cell count?
To account for variations in percentage counts that may be misleading
Why should the total white blood cell count be corrected if more than 5 nucleated red blood cells are observed?
To prevent the underestimation of white blood cell counts
What would be the absolute count of monocytes in a total white blood cell count of 48,000/uL, if monocytes make up 1%?
960/uL
Why is it important to calculate absolute values in interpreting differential count results?
To correct misleading percentages and provide accurate counts
What is the significance of identifying more than 5 nucleated red blood cells (NRBC) during a differential count?
Indicates a possible issue with red blood cell production
In a differential cell count, why is it important to calculate both relative percentages and absolute values?
To ensure accurate representation of each cell type present
What is the main reason for correcting the total white blood cell count when nucleated red blood cells are observed during a differential count?
To prevent overestimation of white blood cell counts
What is one of the challenges in interpreting differential count results based solely on relative percentages?
Risk of misinterpretation due to variations in total white blood cell counts
What characteristic features are associated with monocytes?
Variable shape, kidney-bean shaped or elongated nucleus, sky blue cytoplasm
What function is primarily associated with tissue macrophages?
Initiation of the immune response
What is the major function of monocytes?
Phagocytosis
How are tissue macrophages commonly referred to when they enter tissues?
Macrophages
Which leukocyte type is involved in cleaning up debris that remains after inflammation or infection is cleared?
Monocyte
What type of infection do increased numbers of monocytes typically indicate?
Bacterial infection
Which leukocyte type is known to have the largest size among white blood cells?
Monocyte
What is the cytoplasm color associated with large lymphocytes?
Sky blue
What is the purpose of counting a minimum of 100 WBCs in a relative blood count?
To record the number of each WBC as a percentage
What part of a complete differential count is focused on using an oil objective lens?
Calculating the absolute values for each cell type
What characteristic differentiates eosinophils from neutrophils when performing a differential count?
Their relative bluish and denser staining cytoplasm
Which leukocyte type is primarily responsible for phagocytosis?
Neutrophils
How are quantities of cells expressed in a differential count?
As a percentage of the total 100-cell count
What characteristic describes broken or smudge cells during a differential count?
They are ignored in the classification process
In differential counts, how is the relative blood count different from the automated analyzer?
The relative count records WBCs as percentages while the analyzer counts absolute numbers
What is the primary function of large lymphocytes?
Developing into smaller lymphocytes
In a differential cell count, what is a characteristic feature of medium to large lymphocytes?
Sky blue cytoplasm
What distinguishes tissue macrophages from monocytes in the blood?
Presence in filter organs
Why do increased numbers of monocytes in circulation often indicate infection?
Enhanced phagocytic activity
Which characteristic feature is used to differentiate between immature and mature granulocytes in blood samples?
'Lobed' or 'amoeboid' chromatin
What is the major function of tissue macrophages within the immune system?
Cleaning up debris after infection
In a differential count, what is the significance of ensuring a quality blood smear with a monolayer?
To ensure accurate quantification of cells
Why are broken or smudge cells typically ignored when quantifying cells through a differential count?
To maintain the integrity of the cell count
How are quantities of cells expressed in a differential count?
As a percentage of the total 100-cell count
What is the primary purpose of calculating absolute values for each cell type during a systematic evaluation of white blood cells?
To quantify the actual number of each cell type present
What is the next step after quantifying white blood cells based on a relative blood count that involves counting, identifying, and recording 100 WBCs?
Calculating the percentage of each cell type present
Why are immature leukocytes often excluded from the total 100 WBC count when performing a differential?
To focus primarily on mature and identifiable cell types
What is the main reason for multiplying the total white blood cell count by the percentage of each cell type in a differential count?
To determine the absolute value of each cell type
In a differential cell count, if a sample has 6000/µL total WBC count and 80% neutrophils, what would be the absolute count of neutrophils in the sample?
5760/µL
What is the significance of identifying neutrophils with segmented nuclei in a differential cell count?
Indicates bacterial infection
Why must the WBC count be corrected if more than 5 Nucleated RBCs (NRBC) are seen during a differential count?
To ensure accurate WBC count
What is the primary purpose of calculating both relative percentages and absolute values in interpreting differential count results?
To provide a comprehensive assessment of cell types
In a differential count, why is it important to differentiate between immature and mature granulocytes?
To assess neutrophil function
Study Notes
Differential Count
- The primary purpose of performing a differential count is to identify and quantify different types of white blood cells (WBCs) in a blood sample.
White Blood Cells (WBCs)
- Quantities of cells are expressed as a percentage of the total WBC count and as absolute values (per microliter, μL).
- There are five main types of WBCs: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
Neutrophils
- Characterized by multilobed nuclei and pink-staining cytoplasm.
- The most abundant type of WBC in healthy individuals.
- Involved in phagocytosis, primarily responsible for fighting bacterial infections.
Lymphocytes
- Characterized by a large nucleus and scant cytoplasm.
- Play a crucial role in cell-mediated immunity.
- Can differentiate into plasma cells.
Monocytes
- Characterized by a large, kidney-shaped nucleus and pale-blue staining cytoplasm.
- Mature into macrophages in tissues.
- Involved in phagocytosis and play a key role in fighting infections.
Eosinophils
- Characterized by bilobed nuclei and red-staining granules.
- Involved in parasitic infections and allergic reactions.
- Recognizable at the metamyelocyte stage of development.
Basophils
- Characterized by a small, darkly staining nucleus and sparse, dark-blue staining cytoplasm.
- Involved in allergic reactions and inflammation.
- Rarely seen in peripheral blood smears.
Differential Count Procedure
- Involves counting and identifying 100 WBCs under an oil objective lens.
- Broken or smudge cells are typically ignored due to difficulty in identification.
- Nucleated red blood cells (NRBCs) may be present and should be corrected for if more than 5 are observed.
Calculating Absolute Values
- Essential for interpreting differential count results.
- Involves multiplying the total WBC count by the percentage of each cell type.
Function of WBCs
- Neutrophils: primarily responsible for phagocytosis and fighting bacterial infections.
- Lymphocytes: involved in cell-mediated immunity and can differentiate into plasma cells.
- Monocytes: mature into macrophages in tissues and are involved in phagocytosis and fighting infections.
- Eosinophils: involved in parasitic infections and allergic reactions.
- Basophils: involved in allergic reactions and inflammation.
Test your knowledge on identifying different blood cells in dogs and cats based on their features and characteristics. Explore terms like penia, philia, cytosis, and normal values for WBC. Practice differentiating between cell types using an electronic cell counter and WBC differential count.
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