CHO-K1 cell number response was measured with ab112119. CHO-K1 cells at 0 to 10,000 cells/well/100 µL were seeded overnight in a black wall/clear bottom 96-well plate. The cells were incubated with 20 µL/well of Assay Solution for 3 hours at 37 °C. The absorbance intensity was measured at 570 nm and 605 nm. The fluorescence intensity was linear (R2 = 0.998) to the cell number as indicated. The detection limit from the blank controls was 60 cells/well (n=6).