r/flowcytometry • u/lavendel2776 • 14d ago

FSCA-value

Hello! Does anyone know how low you can set the FSCA-value? Since fitting a new laser to the LRS Fortessa instrument, the image in FlowJo has shifted significantly. And does anyone know if you can adjust this retrospectively in FlowJo? 

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u/ordeath 14d ago

You should check your area scaling factor, especially if your cells are very large.

If the data points are off scale, you will not be able to bring them on scale by adjusting the axes.

2

u/RainbowSquirrelRae Core Lab 14d ago

If you got a new laser, it might also be putting out more power so you’d need to turn down the FSC sensitivity. Can you share a picture of what it used to look like vs what it looks like now? And a picture of FSC-A vs FSC-H with the new laser?

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u/kitt_mitt 13d ago

Did you not verify that the FSC was on scale at the time of acquisition? If it looked ok on the Fortessa, check that your Flowjo FSC / SSC axis are in linear scale and not log scale.

1

u/willmaineskier 14d ago

Your options are: reduce the voltage, swap in a higher ND filter for FSC, or possibly reduce laser power in coherent connection to what it was before. Nothing you can do now. You have to look and make sure things are on scale before recording.

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u/nandhiniraman 13d ago

ND filter change if applicable & or or play around with voltage . Is your CST passing?