Hi, I used XF24 seahorse for mito stress test in HepG2. Then, I got non-mitochondrial consumption for Ctrl vehicle is 6.20 to -23.6. Here, I would like to know if it is possible for the value to be less than zero. I used 2.5 uM oligo, 1.5 uM FCCP, and 0.5 uM rot/AA with HepG2 40000 cells per well. I got basal respiration 49 to 67.