Flow cytometer records very few events per second during sample acquisition, requiring extended run times to collect sufficient data. Analysis shows inadequate cell counts for statistically meaningful conclusions.
Common Causes
1Low cell concentration in sample (below 1x10^5 cells/mL), often due to cell loss during preparation, permeabilization, or fixation steps
2Cell clumps blocking tubing and preventing single-cell stream required for flow cytometry
3Excessive necrosis or apoptosis during sample preparation reducing viable cell numbers
Solutions
1Adjust cell concentration to 1x10^6 cells/mL (optimal range 1x10^5 to 1x10^6); handle cells carefully during all preparation steps to minimize loss
2Mix sample gently immediately before running to dissociate clumps; filter cells through 30 μm nylon mesh in extreme cases to remove aggregates
3Keep wash buffers and reagents at 4°C during preparation to minimize necrosis and apoptosis; work quickly to reduce cell stress; ensure proper storage conditions