ISAC Data Analysis and Interpretation 2

Question 1

In flow cytometry, what does the term 'spread' refer to when evaluating instrument performance?

Accepted Answer

The CV of a bead population measured on a single parameter

Answer

Spread refers to the coefficient of variation (CV) of a bead population, indicating how tightly the instrument measures a single parameter.

Question 2

Which gating strategy is BEST suited for identifying rare populations that overlap with more abundant cells?

Accepted Answer

Hierarchical sequential gating with Boolean combinations

Answer

Hierarchical sequential gating combined with Boolean logic progressively enriches for rare populations by eliminating unwanted cells step-by-step.

Question 3

What is the primary purpose of performing a fluorescence minus one (FMO) control?

Accepted Answer

To set the gate boundary for a specific marker by showing background spread

Answer

FMO controls reveal the spread of fluorescence into a detector from all other fluorochromes except the one being gated, defining the true boundary of negative populations.

Question 4

When using viSNE (t-SNE based visualization) for high-dimensional cytometry data, each point on the map represents:

Accepted Answer

An individual cell from the original dataset

Answer

In viSNE, each point represents a single cell, with proximity on the map reflecting similarity in high-dimensional marker expression.

Question 5

A researcher notices that their CD4 and CD8 staining produces a population with double-positive cells that should not exist physiologically in peripheral blood. What is the MOST likely cause?

Accepted Answer

Insufficient compensation for spectral overlap between the fluorochromes used

Answer

Inadequate compensation causes spillover fluorescence to falsely elevate signal in adjacent channels, creating artifactual double-positive populations.

(ISAC) International Society for the Advancement of Cytometry Practice Test

(ISAC) International Society for the Advancement of Cytometry Practice Test

ISAC Data Analysis and Interpretation 2