Panel Design and Fluorochrome Selection Flashcards

What is the primary consideration when selecting fluorochromes for a multicolor flow cytometry panel?

Answer: Spectral overlap between fluorochromes

Spectral overlap between fluorochromes is the primary concern because emission bleed-through into neighboring channels requires compensation, which can degrade resolution.

In panel design, a bright fluorochrome like PE should ideally be assigned to which type of marker?

Answer: Dimly expressed or rare markers

Assigning bright fluorochromes like PE to dimly expressed antigens maximizes signal from those targets and improves their detection above background.

What is spectral spillover in flow cytometry?

Answer: Detection of one fluorochrome's emission in another fluorochrome's detection channel

Spectral spillover occurs when a fluorochrome's emission spectrum extends beyond its primary detection channel into channels designated for other fluorochromes.

Which parameter is most important for evaluating fluorochrome brightness in the context of panel design?

Answer: Staining index

The staining index quantifies the separation between positive and negative populations relative to background spread, making it the most practical measure of effective brightness for panel decisions.

What is a tandem dye in flow cytometry?

Answer: A fluorochrome consisting of two energy-coupled dyes that shift emission to a longer wavelength

Tandem dyes couple a donor fluorochrome to an acceptor via FRET, so energy absorbed by the donor is transferred and emitted at the acceptor's longer wavelength.

Why is minimizing spectral overlap between fluorochromes a key goal in panel design?

Answer: It reduces compensation requirements and preserves signal resolution

Less spectral overlap means less spillover to correct, and since compensation mathematically increases variance, minimizing it preserves the resolution between positive and negative populations.

Which laser is most commonly used to excite FITC and propidium iodide (PI) in flow cytometry?

Answer: Blue laser (488 nm)

The 488 nm blue laser efficiently excites FITC and PI because both fluorochromes have strong absorption peaks near this wavelength.