SCYM Flow Cytometry Principles 4

Question 1

What does the acronym 'MESF' stand for in flow cytometry standardization?

Accepted Answer

Molecules of Equivalent Soluble Fluorochrome

Answer

MESF (Molecules of Equivalent Soluble Fluorochrome) is a quantitative unit used to standardize fluorescence intensity measurements across instruments.

Question 2

Which of the following is a consequence of under-compensation in multicolor flow cytometry?

Accepted Answer

Populations appear falsely positive in the channel receiving spillover

Answer

Under-compensation leaves residual spillover signal in adjacent channels, making cells appear falsely positive for markers they do not express.

Question 3

Which sample preparation step is critical for accurate immunophenotyping of whole blood?

Accepted Answer

Lysing red blood cells to reduce background interference

Answer

Red blood cell lysis is essential for whole blood immunophenotyping to remove erythrocytes that obscure leukocyte populations.

Question 4

In spectral flow cytometry, how is unmixing different from traditional compensation?

Accepted Answer

Unmixing uses a single reference spectrum per fluorochrome across all detectors, while compensation corrects pairwise spillover

Answer

Spectral unmixing uses the full emission spectrum of each fluorochrome across all detectors simultaneously, providing more accurate signal separation than pairwise compensation.

Question 5

Why is it important to use the same lot of antibody conjugate for compensation controls as for the experimental sample?

Accepted Answer

Different lots may have different fluorochrome-to-protein ratios affecting spillover values

Answer

Fluorochrome-to-protein (F/P) ratios can vary between lots, altering spectral properties and spillover values, so the same lot ensures accurate compensation.

(SCYM) Specialist in Cytometry Practice Test

(SCYM) Specialist in Cytometry Practice Test

SCYM Flow Cytometry Principles 4