Incorrect Fluorescence Compensation and Spectral Overlap
Symptom
Flow cytometry multicolor panels show false-positive signals in channels not expected to be positive. Positive populations appear in multiple fluorescence channels due to spectral overlap between fluorochromes, making accurate population identification impossible.
Common Causes
1Fluorescence compensation not performed or set up incorrectly to correct for spectral overlap between fluorochromes
2Single-color controls not properly prepared, gated, or used for compensation matrix setup
3Mismatch between bright fluorochromes and low-expressing antigens, or dim fluorochromes paired with high-density antigens in multicolor panels
Solutions
1Set up positive single-color controls correctly on flow cytometer; ensure controls are properly gated to capture all events; perform compensation using single-stained samples for each fluorochrome
2Use compensation beads as alternative to cells for creating compensation matrix, especially when cell-based controls are difficult to prepare
3Consult published data for antigen density in specific cell types; pair highly fluorescent dyes with low-expression antigens; use flow cytometry panel builder tools to match fluorochromes with antigens based on expression levels