negative values for gMFI

Hello,

 

I'm looking at an FMO tube for PD-1 which has been stimulated with SEB.
I was curious as to whether anyone has ever encountered a negative gMFI.
I'm not sure as to how this makes sense.  When I look at the histogram,
there are defiantly peaks which show up to the left of the zero.  If the
value is negative for the FMO, is it justifiable to add this to your
sample values to get your specific gMFI value?	Can someone please
explain how a negative FMO is obtainable?  Does it have something to do
with a bivariate scale?

 

Thanks,

 

Tina Powell

University of Colorado HSC