Lab measurements are automatically standardized by the LLN and ULN such that the line is drawn at k*ULN of the y -axis lab test, where k is the integer chosen in this field. Electrocardiogram measurements are plotted on their original scale. Vital signs measurements are plotted on their original scale.To Set a Reference Line for the y- Axis of the Bubble Plot:Tip : To change the scale of the slider, right-click on the slider and select from the pop-up menu. Change the upper or lower boundaries in the that appears, to rescale the slider and click .