ISAC Analytical Methods and Techniques 2

Question 1

Which compensation method corrects for spectral overlap between fluorochrome channels in flow cytometry?

Accepted Answer

Single-color controls with compensation matrix

Answer

Single-color controls are used to build a compensation matrix that mathematically removes signal spillover between detector channels.

Question 2

In spectral flow cytometry, what is the primary advantage over conventional flow cytometry?

Accepted Answer

Full spectral signature capture enabling better unmixing of fluorochromes

Answer

Spectral flow cytometry captures the full emission spectrum of each fluorochrome, allowing autofluorescence separation and better resolution of spectrally similar dyes.

Question 3

What does the term 'staining index' measure in flow cytometry panel design?

Accepted Answer

The separation between positive and negative populations relative to background noise

Answer

Staining index quantifies how well a fluorochrome separates positive from negative populations by comparing the difference in median fluorescence to the spread of the negative population.

Question 4

Which light source is most commonly used in modern cell sorters for high-speed applications?

Accepted Answer

Solid-state diode laser

Answer

Solid-state diode lasers provide stable, coherent, monochromatic illumination and are standard in high-speed cell sorters due to their reliability and power consistency.

Question 5

When setting up a cell viability assay using a live/dead discriminator dye, why must dead cells be excluded?

Accepted Answer

Dead cells bind antibodies non-specifically, causing false positives

Answer

Dead cells have compromised membranes that allow non-specific antibody binding, leading to artifactual false-positive staining and misidentification of cell populations.

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

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

ISAC Analytical Methods and Techniques 2