Hematology Week 8 Canvas Questions
What is the absolute lymphocyte count if 46% lymphocytes are counted in the differential count of a blood specimen with a total WBC count of 11.5 × 103/μL?
5.29 x 103/μL
Which of the following conditions is the leading cause of hospitalization for sickle cell patients? A)Acute chest syndrome B)Splenic sequestration C)Painful crisis D)Priapism
A)Acute chest syndrome
When nucleated red blood cells are present, a correction is necessary on total WBC because: A)Nucleated red blood cells are counted as leukocytes. B)Nucleated red blood cells are confused with platelets C)The erythrocyte count is too low. D)The leukocyte count should be higher
A)Nucleated red blood cells are counted as leukocytes
Which of the following hemoglobin separation methods is used for most newborn hemoglobin screening? A)Acid electrophoresis B)Isoelectric focusing C)Alkaline electrophoresis D)High-performance liquid chromatography
B)Isoelectric focusing
Which of the following statements pertaining to most of the clinically significant hemoglobin variants? A)Most are extensions of the amino acid chain B)Most are single amino acid substitution C)Most are synthetic defects D)Most are fusion hemoglobins
B)Most are single amino acid substitution
What could cause the number of band cells to be increased above normal?
Bacterial infection
Which of the following factors contributes to the pathophysiology of sickling? A)Fava beans B)Increased iron concentration C)Dehydration D)Hypochromia
C)Dehydration
Which hemoglobins migrate to the same location at pH 8.6? A)Hgb D, Hgb O, Hgb F B)Hgb F, Hgb H, Hgb Barts C)Hgb A2, Hgb C, Hgb E D)Hgb A2, Hgb S, Hgb C
C)Hgb A2, Hgb C, Hgb E
Which of the following hemoglobins ranks second invariant hemoglobins worldwide? A)Hgb C B)Hgb S C)Hgb E D)Hgb H
C)Hgb E
All but one of the following may be seen in the peripheral smear when a sickle crisis has occurred. A)Polychromasia B)Target cells C)Moderate elliptocytes D)Nucleated red blood cells
C)Moderate elliptocytes
Which of the following shows crystals appearing like bars of gold in the peripheral smear? A)Hgb SS disease B)Hgb DD disease C)Hgb EE disease D)Hgb CC disease
D)Hgb CC disease
What is the amino acid substitution in sickle cell anemia patients? A)Adenine for thymine B)Lysine for valine C)Cytosine for guanine D)Valine for glutamic acid
D)Valine for glutamic acid
Why is it important to correctly identify blood cells?
It is important to determine WBC percentages and identify any cell abnormalities present; 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.
Define atypical lymphocyte
Lymphocyte, usually large, that occurs in response to viral infection and is common in infectious mononucleosis; reactive lymphocyte
Define anisocytosis
Marked variation in the size of erythrocytes
What are the functions of neutrophils? Of monocytes? Of lymphocytes?
Neutrophils fight bacterial infections and are active in phagocytosis; monocytes are active in phagocytosis and in processing antigens; lymphocytes produce antibodies and messenger molecules (cytokines).
Contrast the appearance of normochromic RBCs and hypochromic RBCs.
Normochromic red blood cells (RBCs) stain evenly, with only a small pale area in the center of the cells. Hypochromic RBCs have less than the normal amount of hemoglobin; a narrow ring of hemoglobin is visible around the outer edge of the cell, and a large central area of pallor is present.
Describe the area of the smear in which the differential count should be performed.
Perform the count 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 lymphocytes and name one condition that causes them.
See Figure 2-61. 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 lymphocyte cytoplasm may stain more intense blue than the sky-blue cytoplasm of typical small lymphocytes.
How many platelets should be noted per oil-immersion field on a smear if the platelet count is normal?
Seven to 20 platelets per oil-immersion field indicates a normal platelet count.
What safety hazards are associated with performing the WBC differential count?
Stained blood smears do not represent a biological hazard. However, physical hazards are present in the procedure, such as potential cuts from glass microscope slides and electrical hazards associated with use of the microscope.
How is an absolute WBC count calculated?
The absolute count is obtained by multiplying the WBC count by the percentage of each type of white blood cell counted during the differential procedure.
List the five types of WBCs, and state the adult reference ranges in percentages.
The adult reference ranges are neutrophils, 50% to 65%; bands, 0% to 7%; eosinophils, 1% to 3%; basophils, 0% to 1%; lymphocytes, 25% to 40%; and monocytes, 3% to 9%. See Table 2-12 for ranges for other age-groups.
What is the purpose of a WBC differential count?
The purpose of the differential count is to classify WBCs into different types and determine the relative frequency of each WBC type in the peripheral blood
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.
Define differential count
a determination of the relative numbers of each type of white blood cells when a specified number (usually 100) is counted; leukocyte differential count; white blood cell differential count
What three characteristics of WBCs are evaluated in cell identification?
a. Relative cell size b. Nuclear characteristics c. Cytoplasmic characteristics
Define macrocytic
having a larger than normal cell size
Define normocytic
having a normal cell size
Define normochromic
having normal color
Define hypochromic
having reduced color or hemoglobin content
Define microcytic
having smaller than normal cell size
Define poikilocytosis
significant variation in the shape of red blood cells.
Define phagocytosis
the engulfing of a foreign particle or cell by another cell
