Lesson 2-9

What is the adult reference range for basophils?

0-1%

What is the adult reference range for band cells?

0-7%

What is the adult reference range for eosinophils?

1-3%

What is the adult reference range for lymphocytes?

25-40%

What is the adult reference range for monocytes?

3-9%

What is the adult reference range for neutrophils?

50-65%

How many platelets should be notes per oil-immersion field on a smear if the platelet count is normal?

7-20 platelets

What are the function of monocytes?

Active in phagocytosis and in processing antigens.

What could cause a the number of band cells to be increased above normal?

Bacterial infection

How is and absolute WBC count calculated?

By multiplying the WBC count by the percentage of each type of WBC counted during the differential procedure.

What are the functions of neutrophils?

Fight bacterial infections and are active in phagocytosis.

Describe the area of the smear in which the differential count should be performed.

In an area in the feathered edge of the smear where the red cells are just touching but not overlapping.

Describe the appearance of atypical RBC's and one condition that causes them.

Most atypical lymphocytes are larger than small lymphocytes and are characterized by a large nucleus and a large amount of blue cytoplasm easily indented by RBCs. These indentations cause the lymphocytes to have a holly-leaf appearance. The atypical cytoplasm may stain more intense blue than the sky-blue cytoplasm of typical small lymphocytes.

Contrast the appearance of normochromic RBCs and hypochromic RBCs.

Normochromic RBCs stain evenly with only one small area of pallor in the center. Hypochromic RBCs have less hemoglobin creating a halo around the outer edge of the cell and a large area of pallor in the center.

What safety hazards are associated with performing the WBC differential count?

Potential cuts from glass microscope slides, and electrical hazards associated with use of the microscope.

What are the function of lymphocytes?

Produce antibodies and messenger molecules (cytokines).

What three characteristics of WBC's are evaluated in cell identification?

Relative size, nuclear characteristics, and cytoplasmic characteristics.

Why is it important that differential counts only be performed and reported by experienced, qualified personnel?

The results of the differential count can lead to a variety of actions such as a diagnosis, institution of treatment, or further testing. It is imperative that only qualified personnel be allowed to perform and report differential counts so that results are reliable. It is crucial that abnormal cells be recognized and identified correctly so that a potentially serious condition is recognized as soon as possible.

Why is it important to correctly identify blood cells?

This information can be important in diagnosis and treatment of certain diseases such as anemias, leukemias, other blood diseases, as well as diseases and conditions that arise in other parts of the body such as infections.

What is the purpose of a WBC differential count?

To classify WBCs into different types and determine the relative frequency of each EBC type in the peripheral blood.