Home Immunology Cell Preparation for Flow Cytometry
Steps
  1. 1 Determine cell type and sample source 00:05
  2. 2 Handle cells at appropriate temperature 01:09
  3. 3 Lyse erythrocytes using appropriate buffer 01:27
  4. 4 Process samples promptly or preserve them 02:02
  5. 5 Remove dead cells and debris 02:57
  6. 6 Prepare adherent cells with gentle lifting 03:41
  7. 7 Stimulate cells under optimized conditions 04:00
Immunology BD Biosciences

Cell Preparation for Flow Cytometry

Protocol
Difficulty
intermediate

Steps

1
Determine cell type and sample source

Identify what type of cells you are analyzing, such as whole blood, PBMCs, tissue, or cell lines. Consider that rare lymphoid populations benefit from PBMC isolation, while granulocyte analysis requires whole blood.

▶ 00:05
2
Handle cells at appropriate temperature

Keep whole blood at room temperature, but maintain PBMCs and cells in BD effects lacing solution on ice to preserve cell viability and morphology.

▶ 01:09
3
Lyse erythrocytes using appropriate buffer

Use either BD effects lacing solution (which contains fixative) or BD FarmLite buffer (without fixative) to remove red blood cells. Stain for fixative-sensitive antigens before using BD effects lacing solution.

▶ 01:27
4
Process samples promptly or preserve them

Analyze samples immediately after collection to prevent changes in surface phenotype. If immediate processing is not possible, freeze or fix cells to preserve them for later use.

▶ 02:02
5
Remove dead cells and debris

Filter samples through a cell strainer to remove clumping cells and dead cells. Use a viability marker to gate out dead cells and improve analysis quality and population resolution.

▶ 02:57
6
Prepare adherent cells with gentle lifting

For cultured adherent cells, use gentle lifting media such as EDTA or accutase instead of trypsin to prevent cleavage and loss of sensitive surface markers.

▶ 03:41
7
Stimulate cells under optimized conditions

Stimulate cells directly in whole blood or culture PBMCs and tissue-derived cells with appropriate medium, duration, and temperature. Note that phosphorylation assays require only minutes while cytokine assays require hours of incubation.

▶ 04:00

🚨 Failure Case Library (20) + Submit your own case

critical
Excessive Autofluorescence in Solid Tissue Samples
Solid tissue samples display much higher autofluorescence than PBMCs across multiple channels. Tissue-derived cells show elevated background due to structural proteins, extracellular matrix components, and pigments.
💡 5 · ✓ 5
critical
Phosphorylation Artifacts from Pre-Staining Surface Antibodies
Intracellular phosphorylation signals are artifactually elevated or altered when surface antibodies are added before fixation. Antibody binding to surface antigens triggers unwanted intracellular signaling cascades that confound phospho-flow results.
💡 5 · ✓ 6
critical
Inadequate Pathogen Inactivation in Infectious Samples
Samples from infected or potentially hazardous sources show signs of incomplete inactivation, creating biosafety concerns during handling and flow cytometry analysis. Validation assays indicate residual infectious potential.
💡 4 · ✓ 6
severe
High Background Signal from Autofluorescent Cell Types
Elevated background fluorescence intensity across multiple channels, particularly affecting green (FITC) and orange (PE) channels. Difficult to distinguish specific antibody staining from background noise.
💡 5 · ✓ 5
severe
Aldehyde-Based Fixation Amplifying Autofluorescence
Fixed cell samples exhibit dramatically elevated autofluorescence compared to live cells, particularly in green and UV channels. Background signal increases after fixation protocol, reducing signal-to-noise ratio.
💡 4 · ✓ 5
severe
Isotype Control Signal Is Abnormally High
The isotype control antibody shows unexpectedly high fluorescence signal, making it difficult to distinguish true positive staining from background in flow cytometry analysis.
💡 6 · ✓ 6
severe
Excessive Background in Myeloid-Rich Cell Populations
Samples enriched for monocytes, macrophages, or dendritic cells show uniformly high fluorescence across all antibody channels including isotype controls, obscuring specific marker detection.
💡 4 · ✓ 5
severe
Incomplete Cell Fixation Due to Insufficient Incubation
Cells show inconsistent staining patterns, continued metabolic activity, or poor storage stability when fixation incubation time is too short. Inadequate fixation may also fail to inactivate infectious samples properly.
💡 5 · ✓ 6
severe
Incorrect Positive/Negative Cell Population Ratios
The measured ratio of positive to negative cells for a given marker appears inaccurate or inconsistent. Background signals are not correctly measured, leading to improper gating and incorrect population quantification.
💡 4 · ✓ 4
severe
Poor Resolution of Dim Markers Masked by Autofluorescence
Low-expression markers become indistinguishable from background. Positive and negative populations show poor separation, with dim fluorophores completely masked by cellular autofluorescence.
💡 4 · ✓ 5
moderate
High Non-Specific Binding After Cell Fixation
Following fixation with formaldehyde or paraformaldehyde, both test antibodies and isotype controls show elevated background signal and increased non-specific staining patterns.
💡 4 · ✓ 5
moderate
Cell Morphology Distortion and Loss of Scatter Properties
Forward scatter (FSC) and side scatter (SSC) profiles show abnormal patterns after fixation. Cell populations cluster abnormally, size measurements are inconsistent, and gating strategies based on morphology fail to resolve expected populations.
💡 4 · ✓ 4
moderate
Progressive Biological Changes in Unfixed Time-Course Samples
Time-course experiments show artifactual progression or decay of signals when samples are not fixed at each timepoint. Biological processes continue during sample handling, obscuring true temporal snapshots.
💡 5 · ✓ 6
moderate
Non-specific Antibody Binding Creating Noise
Antibody binds non-specifically to cells of interest, resulting in noisy data and elevated background. True marker expression cannot be distinguished from non-specific binding events.
💡 4 · ✓ 5
moderate
Isotype Control Does Not Match Test Antibody Background
Isotype control fails to accurately represent the non-specific binding background of the test antibody. Background levels measured by isotype control differ significantly from actual test antibody background.
💡 4 · ✓ 5
moderate
Autofluorescence Complicating Cell Population Gating Strategy
Difficult to establish clear gates between positive and negative populations. Autofluorescent cells appear in unexpected regions of scatter plots, creating ambiguous boundaries and potential misidentification of cell populations.
💡 4 · ✓ 5
moderate
Sample Degradation During Delayed Analysis Storage
Samples fixed for next-day or multi-day analysis show progressive signal loss, increased debris, and population shifts compared to immediate analysis. Data quality deteriorates with storage time despite initial proper fixation.
💡 5 · ✓ 6
moderate
Inconsistent Fixation Quality from Incorrect PFA Concentration
Samples show variable fixation quality, with some cells over-fixed (high autofluorescence, poor staining) and others under-fixed (continued biological activity). Reproducibility across experiments is compromised.
💡 5 · ✓ 6
moderate
Background Spread Due to Spillover Not Corrected
Even after compensation, background spread from spillover effects makes it difficult to determine appropriate gate boundaries. Positive and negative populations are not clearly separated in the detector of interest.
💡 4 · ✓ 4
moderate
High Background in Biological Control Sample
Biological control (e.g., unstimulated sample in stimulation assay) shows unexpectedly high background, making it difficult to set clear positive/negative boundaries.
💡 4 · ✓ 5
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