Cellular Detection: Flow Cytometry, FACS, and CyTOF
Under scientific review
This introductory page is under scientific review. Use it for orientation, not clinical decision-making.
TL;DR
Flow cytometry measures markers on or inside single cells in suspension. FACS adds sorting, so selected cells can be collected. CyTOF/mass cytometry replaces fluorescent labels with metal tags, increasing marker count while sacrificing live-cell sorting. These methods are central for immunophenotyping, leukemia/lymphoma work, tumor microenvironment studies, and cell-therapy manufacturing. Sources: [1], [2]
What it measures
| Measurement | Example |
|---|---|
| cell size/granularity | FSC/SSC |
| surface markers | CD3, CD4, CD8, CD19, PD-1 |
| intracellular proteins | FOXP3, cytokines, phospho-signaling |
| viability | live/dead stains |
| cell cycle/DNA content | DNA-binding dyes |
| function | degranulation, cytokine capture, proliferation |
Flow vs FACS vs CyTOF
| Method | Best for | Caveat |
|---|---|---|
| Flow cytometry | fast multiparameter cell profiling | compensation, autofluorescence |
| FACS | sorting viable populations | stress, purity/yield tradeoff |
| CyTOF | high-dimensional immune profiling | no live-cell recovery, lower throughput |
Common outputs
- FCS files
- compensation matrix
- gating hierarchy
- marker intensity matrix
- cluster labels
- sorted-cell metadata
- QC for viability and doublets
Failure modes
- bad antibody panel design
- spectral overlap or compensation errors
- dead-cell artifacts
- doublets
- batch effects
- over-gating by eye
- tissue dissociation bias
- losing fragile or adherent cell types
Developer notes
- FCS files should be stored with panel metadata and compensation/spillover matrices.
- Gating is an analysis decision; preserve the hierarchy and thresholds.
- Batch correction cannot recover cell types lost during dissociation.
- Marker intensity is not comparable across instruments without controls.
- Sorted populations need purity, yield, and viability metadata.
- Automated clustering should be checked against known biology and manual gates.
References
- Chan A, Au R, Gao Q, et al. Role of flow cytometric immunophenotyping in the diagnosis of breast implant-associated anaplastic large cell lymphoma. Cytometry B Clin Cytom 2024;106:117-125. PMID 38297808. https://doi.org/10.1002/cyto.b.22162
- Bendall SC, Simonds EF, Qiu P, et al. Single-cell mass cytometry of differential immune and drug responses across a human hematopoietic continuum. Science 2011;332:687-696. PMID 21551058. https://doi.org/10.1126/science.1198704