Deck 40: Flow Cytometry

Question 1

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

A) Monoclonal
B) Clonal
C) Tumorigenic
D) Contour gated

Answer 1

Clonal

Question 2

An HIV-positive patient has his blood drawn to get his CD4 count. His results are as follows: WBC count: 2.0 × 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?

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

Answer 2

The patient's absolute CD4 count is 300/mcL, and he does not have AIDS.

Question 3

The following are accurate statements regarding fluorochromes except which one?

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) They contribute to the scattered light caused by a cell when it travels through the flowcell.

Answer 3

They contribute to the scattered light caused by a cell when it travels through the flowcell.

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

Neoplasms are made up of a population of identical cells or a clone of cells. When identified, the clone can lead to the discovery of a lymphoid malignancy or other lymphoproliferative disorder. Clonality be detected by:

A) The uniform expression of one immunoglobulin light chain
B) A mixture of cells with either kappa or lambda light chains
C) A surface immunoglobulin detection
D) The bright intensity of all monoclonal markers

Question 6

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. What calculations does the dual platform use to determine the absolute number of CD4 positive cells?

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

Question 7

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) Lack of specificity

Question 8

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

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

Question 9

Of the following, which is not an appropriate specimen for flow cytometry?

A) Blood
B) Bone marrow
C) Lymphoid tissue
D) Plasma

Question 10

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

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

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

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) Relative CD4 count

Question 13

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) Neutrophils
B) T cells
C) B cells
D) Monocytes

Question 14

Which of the following is not the component(s) of a flow cytometer?

A) Photomultiplier tubes
B) Sheath fluid
C) Flow chamber
D) Hemoglobin chamber

Question 15

A blood sample from a patient 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 16

The flow cytometer contains a flow chamber that has two columns of fluid-sample and sheath-maintained at different pressure. 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.

Question 17

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

A) CD19 and CD5
B) CD5 and CD11c
C) CD5 and CD10
D) sIg and CD25

Question 18

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 19

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 20

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 21

CD34 enumeration is useful in bone marrow and peripheral blood stem cell transplantation. For this enumeration, the EWGCCA recommendations include proper technique and interpretation of the flow cytometry analysis. Which of the following standards was 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 22

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

Question 23

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

Question 24

A strategy for determining MRD in AML that has been advocated is:

A) Panel: CD38, CD138 and CD45
B) Panel: CD20/CD38/CD19/CD5
C) "Different than normal"
D) Boolean gating

Question 25

The EWGCCA recommends performing which of the following with CD34 enumeration?

A) Dual staining with CD45
B) DNA index
C) IRF
D) Exclude cells with low levels of CD 45 expression

Question 26

The 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 27

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

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

Question 28

What is the purpose of CD34 count?

Question 29

How is flow cytometry used in cell quantitation?

Question 30

Rituximab, an anti-CD20 antibody, has been found to be effective in treating:

A) Rheumatoid arthritis
B) HIV
C) Breast cancer
D) LAD1

Question 31

The expression of several antigens from two different lineages complicates the categorizing the diagnosis as AML or 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 32

Flow results on a patient sample revealed an absence of CD20 and CD19 on the B-lymphocytes as well as an absence of BTK in monocytes and platelets. What is the most likely diagnosis?

A) Hyper IgM syndrome
B) Chronic granulomatous disease
C) Wiskott-Aldrich syndrome
D) X-linked congenital agammaglobulinemia

Question 33

Immunophenotyping is essential for diagnosing ALL, separating T- and B- lineage ALL, and identifying 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