Deck 36: Flow Cytometry

Question 1

Which of the following is used to standardize the procedure in flow cytometry?

A)Specimen handling
B)Specimen preparation
C)Gating accuracy
D)All of the above

Answer 1

All of the above

Question 2

The flow cytometer contains a flow chamber.This chamber has two columns of fluid maintained at different pressure, sample and sheath fluid.Which of the following statements about the flow chamber is correct?

A)Cells in the outer column become dispersed.
B)The sample fluid has turbulent flow.
C)Cells are aligned in single file in front of the laser.
D)The two columns of fluid differ in color.

Answer 2

Cells are aligned in single file in front of the laser.

Question 3

Which of the following is/are appropriate specimen(s) for flow cytometry?

A)Blood
B)Bone marrow
C)Lymphoid tissue
D)All of the above

Answer 3

All of the above

Question 4

Which of the following is used to determine the relationship between the content of tumor cells and normal dividing cells?

A)The absorbance concentration of the fluorochrome
B)The DNA index
C)The S phase fraction
D)The G2/M phase fraction

Question 5

Which of the following is/are component(s) of a flow cytometer?

A)Photomultiplier tubes
B)Sheath fluid
C)Flow chamber
D)All of the above

Question 6

A single group of cells possessing identical aberrant phenotypes is defined as:

A)Monoclonal.
B)Clonality.
C)Tumorigenic.
D)Contour gating.

Question 7

Which of the following is/are clinical application(s) of flow cytometry?

A)Assessment of total body iron
B)Immunophenotyping
C)DNA amplification
D)Cytogenetic analysis

Question 8

Choose the correct statement regarding the IRF from the choices below:

A)The IRF is directly proportional to the degree of bone marrow turnover.
B)The IRF is indirectly proportional to the average age of the reticulocytes.
C)The IRF cannot be used to monitor erythropoietin therapy.
D)The IRF cannot be used to monitor bone marrow recovery after transplant.

Question 9

An HIV-positive patient has his blood drawn to get his CD4 count.His results are as follows: WBC count: 2.0 x 109/L with 15% lymphocytes.CD4 positive cells are 10% of the total lymphocyte count.What is this patient's absolute CD4 count, and what does this mean for the patient?

A)The patient's absolute CD4 count is 300/uL, and the patient has AIDS.
B)The patient's absolute CD4 count is 180/uL, and the patient has AIDS.
C)The patient's absolute CD4 count is 300/uL, and the patient does not have AIDS.
D)The patient's absolute CD4 count is 120/uL, and the patient does have AIDS.

Question 10

Which two CD markers would be helpful in differentially identifying CLL from hairy cell leukemia?

A)CD19 and CD5
B)CD5 and CD11c
C)CD5 and CD25
D)sIg and CD25

Question 11

The fluorescent dye employed by hematology analyzers to count reticulocytes binds to:

A)DNA.
B)Proteins.
C)RNA.
D)Nucleic acids.

Question 12

The percentage of CD4 positive lymphocytes is determined by flow cytometry using staining with fluorescent-tagged antibodies against CD3 and CD4, followed by whole blood RBC lysis.The dual platform uses what calculation to determine the absolute number of CD4 positive cells?

A)Absolute CD4 count x 100
B)Number of CD4+ cells x 100
C)Absolute lymphocyte count x % CD4+ lymphocytes/100
D)% lymphocytes x % CD4+ lymphocytes/100

Question 13

Neoplasms are made up of a population of identical cells, or a clone of cells.A clone, when identified, can lead to discovery of a lymphoid malignancy or other lymphoproliferative disorder.In what ways can clonality be detected?

A)Uniform expression of one immunoglobulin light chain
B)Mixture of cells with either kappa or lambda light chains
C)Surface immunoglobulin detection
D)Bright intensity of all monoclonal markers

Question 14

Which of the following is considered a drawback of immunophenotyping a suspected acute leukemia?

A)AML NOC
B)Lineage heterogeneity
C)Lack of sensitivity
D)All of the above

Question 15

A flow instrument printout reveals a single scatter population of small size and low complexity.Ninety percent of the cells in that population have CD2 on their surface.What is the most probable lineage of the unknown population?

A)NK cells
B)T cells
C)B cells
D)Monocytes

Question 16

Which markers are useful in immunophenotyping for leukemia/lymphoma of T cell lineage?

A)CD103, CD61, and CD59
B)CD38, CD59, and CD13
C)CD2, CD3, CD4, CD5, CD7, and CD8
D)CD55, CD25, and kappa

Question 17

What is one advantage to using monoclonal antibodies, rather than polyclonal antibodies, in immunophenotyping?

A)They are commercially available.
B)The antigen can be recognized even if some parts of it are abnormal.
C)They have high purity and reproducibility.
D)They can be directly attached to fluorochromes.

Question 18

A patient blood sample suspected of having ALL is received in the flow lab for immunophenotyping.The analysis is performed, and standard B cell markers are present, but the patient is also CD33-positive.What is the most likely reason for this occurrence?

A)The patient has a poorer prognosis than standard ALL.
B)The patient is responding to the chemotherapy.
C)The patient has ALL with aberrant myeloid cellular antigens.
D)It cannot be determined by the information given.

Question 19

Choose the accurate statement(s) regarding fluorochromes from the choices below.

A)They excite at one wavelength and emit light at a different wavelength.
B)They can bind to DNA or RNA.
C)They can be used to label detection antibodies.
D)All of the above

Question 20

In diagnosing PNH, which of the following assays is most sensitive to the detection of the disorder?

A)GPI anchor phenotype
B)Ham test
C)Sucrose lysis test
D)Osmotic fragility test

Question 21

Explain the advantages of using flow cytometry to count reticulocytes.

Question 22

CD34 enumeration is useful in bone marrow and peripheral blood stem cell transplantation.The EWGCCA recommendations for this enumeration include proper technique and interpretation of the flow cytometry analysis.Which of the following standards were recommended for proper acquisition of events?

A)Include platelets and unlysed red blood cells and debris
B)Include only CD34 dim staining populations
C)Use bright fluorochrome conjugates of class II or III monoclonal antibodies that detect all glycoforms of CD34
D)Acquire only 10 CD34 positive cells

Question 23

An increased IRF is seen in which of the following?

A)Erythropoietin therapy
B)Iron therapy in iron deficient patients
C)Bone marrow recovery post-transplant
D)All of the above

Question 24

It is recommended by the EWGCCA to perform which of the following alongside CD34 enumeration?

A)Dual staining with CD45
B)DNA index
C)IRF
D)All of the above

Question 25

An unknown cell resembling a hematogone has CD19 and CD20 antigens.What is the lineage of the unknown cell?

A)Myeloid
B)Monocytic
C)Lymphoid
D)Erythroid

Question 26

Explain why flow cytometry is of limited use in identifying AML.

Question 27

What is the purpose of CD34 count?

Question 28

The expression of several antigens from two different lineages complicates the placement of the diagnosis into categories of AML and ALL.This biphenotypic expression toward more than one lineage restricts the use of immunophenotyping.In differentiating AML and ALL, staining with which of the following cytochemical stains indicates AML?

A)PAS
B)Giemsa
C)Myeloperoxidase
D)Thiazole orange

Question 29

Name at least two pitfalls in immunophenotyping mature lymphoid malignancies, and explain how you would correct this.

Question 30

Immunophenotyping is essential for the diagnosis of ALL, separation of T and B lineage ALL, and identification of subtypes of B lineage ALL.What markers can blasts express in precursor B cell ALL?

A)CD10 and TdT
B)CD1 and CD2
C)CD4 and CD8
D)CD41 and CD61

Question 31

How can flow cytometry be used in cell quantitation?

Question 32

DNA content of a patient's tumor cells is reported as 2.0, and the DNA content of diploid cells is 1.0.What is the DNA index?

A)2.0
B)3.0
C)1.0
D)0.5

Question 33

Cells can be separated during data analysis by gating.This process of isolating cells can be based on what properties?

A)Cell size and granularity
B)Cell density
C)Shape of the nucleus
D)Color of the cytoplasm

Question 34

Which analyte is the best indicator of the overall picture of the immune system in an HIV-positive patient?

A)Absolute CD4 count
B)Relative lymphocyte count
C)WBC count
D)All of the above

Question 35

The gold standard for the diagnosis of AML is based on what information?

A)Immunophenotyping and morphology
B)Morphology and cytogenetic studies
C)Immunophenotyping and cytogenetic studies
D)Cytochemical staining and immunophenotyping