High background in Flow cytometry

Explore possible causes and solutions for a high background or high percentage of positive cells in Flow cytometry.

Why am I experiencing high background/high percentage of positive cells?

Possible causes
Solution
Gain set too high/offset too low.
  • Use the positive control to set up the flow cytometer correctly again, using the offset to reduce background from small particles and reduce the gain to decrease the signal.

Excess antibody.

This can be caused by high antibody concentration or excess antibody remaning.

  • Decrease antibody concentration.

  • Detergent can be added to the wash buffers to ensure any excess antibody is washed away.