Fig. 13From: A sensitive chemiluminescence based immunoassay for the detection of cortisol and cortisone as stress biomarkersCalibration curves showing a the change in the optical density with the increase of cortisol concentration where the red points indicate the cortisol concentrations, and the green points are the error bar for each concentration, b the increase in optical density with a linear trend after subtracting the blank signal from the sample signalBack to article page