SCYM Fluorochrome Selection 3

Question 1

Which fluorochrome combination is contraindicated in the same panel due to direct spectral overlap on the 488 nm laser?

Accepted Answer

FITC and PE

Answer

PE and PE-Cy7

Answer

FITC and PerCP-Cy5.5

Answer

APC and APC-Cy7

Question 2

What is the primary limitation of tandem dyes such as PE-Cy7 compared to pure fluorochromes?

Accepted Answer

Incomplete energy transfer can produce anomalous emission peaks

Answer

They cannot be excited by common lasers

Answer

They have low extinction coefficients

Answer

They require UV excitation

Question 3

For a marker present on only 0.1% of lymphocytes, which fluorochrome brightness tier is most appropriate?

Accepted Answer

Bright (e.g., PE or BV421)

Answer

Dim (e.g., PerCP)

Answer

Intermediate (e.g., FITC)

Answer

Any brightness is equally suitable

Question 4

Which of the following fluorochromes is classified as a 'large Stokes shift' dye, useful for simplifying panel design?

Accepted Answer

Pacific Orange

Answer

PE

Answer

FITC

Answer

BV421

Question 5

APC has its excitation maximum at approximately which wavelength?

Accepted Answer

633–638 nm

Answer

488 nm

Answer

532 nm

Answer

405 nm

Question 6

Which factor most directly affects compensation matrix accuracy when switching lot numbers of a tandem dye?

Accepted Answer

Lot-to-lot variation in FRET efficiency altering spectral characteristics

Answer

Laser power stability

Answer

Buffer composition of the sample

Answer

Cell viability

Question 7

When selecting fluorochromes for surface and intracellular markers in the same panel, which consideration is unique to intracellular staining?

Accepted Answer

Fixation and permeabilization can quench or shift certain fluorochrome emissions

Answer

Intracellular markers always require brighter dyes

Answer

Intracellular dyes must be excited by UV

Answer

Compensation is unnecessary for intracellular staining

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