SCYM Clinical Applications 5

Question 1

In the WHO classification of acute leukemias, what percentage of blasts in bone marrow defines AML (in the absence of recurrent genetic abnormalities)?

Accepted Answer

≥20%

Answer

The WHO 2022 classification requires ≥20% blasts in bone marrow or peripheral blood to diagnose AML without a defining genetic abnormality.

Question 2

Which flow cytometric parameter is most useful for distinguishing reactive plasmacytosis from myeloma plasma cells?

Accepted Answer

Aberrant CD19 loss with CD56 gain and κ/λ light chain restriction

Answer

Myeloma plasma cells typically lose CD19, gain CD56, and show monoclonal light chain restriction, whereas reactive plasma cells are CD19+/CD56-/polyclonal.

Question 3

In the diagnosis of chronic myelomonocytic leukemia (CMML), which flow cytometric finding supports the diagnosis?

Accepted Answer

Expansion of CD14+/CD16- classical monocytes exceeding 94% of monocytes

Answer

CMML is associated with accumulation of classical CD14+/CD16- monocytes comprising ≥94% of circulating monocytes by flow cytometry.

Question 4

Which cytometric approach is used to identify circulating endothelial cells (CECs) as a biomarker of vascular damage?

Accepted Answer

CD146+/CD105+/CD45-/CD31+ cells in peripheral blood

Answer

CECs are identified as CD146+, CD105+, CD31+ cells that are CD45-negative to distinguish them from hematopoietic cells.

Question 5

For detecting antigen-specific T cells (e.g., viral or tumor-specific), which flow cytometry tool uses MHC-peptide complexes to directly stain T cells?

Accepted Answer

Peptide-MHC tetramers

Answer

Peptide-MHC tetramers directly bind the T-cell receptor of antigen-specific T cells, enabling their identification without requiring activation.

(SCYM) Specialist in Cytometry Practice Test

(SCYM) Specialist in Cytometry Practice Test

SCYM Clinical Applications 5