Quadrant Tool

Use the quadrant tool in the Graph window to create quadrant gates. FlowJo implements quadrant statistics by creating four adjacent but nonoverlapping rectangular gates.

When the quadrant tool is selected, FlowJo will track a cross hair over the graph window. When you click on the graph it will display the frequencies of events within each quadrant (these frequencies are the percentage of events falling within each quadrant, with respect to the events that fall in the current subset. Thus, the four frequencies add up to 100%).

The X and Y coordinates of the center of the quadrant gates are shown while you track the mouse. Once you click to select the quadrant position, FlowJo will create four rectangular gates as subsets of the current population. FlowJo names the gates according to the parameters and each quadrant position. A quadrant gate is therefore named as "Q: parmX± parmY±", where parmX and parmY are the X axis and Y axis parameters, respectively, and "±" will reflect whether the quadrant is the higher (+) or lower (-) quadrant for that parameter. (If necessary, FlowJo may truncate the names of the parameter stains such that the overall gate names are not too long).

You may click on the central, shared vertex of quadrants to move all four simultaneously.

When you have quadrant gates on a graph, they cover the entire area of the graph at all times. This means that other gates may be below these gates. To select other gates, press the shift key while clicking on the desired gate.

To get quadrant statistics, simply add the appropriate statistic to each of the quadrants. For instance, you could select the first quadrant in the workspace window, and add the Frequency of parent statistic to get the percentage of that quadrant's subpopulation in the parent population. Click-and-drag this statistic to each of the other four quadrants. (Or, select all four nodes before adding the statistic).