Figure 2: CD4% is plotted as the independent variable on the X-axis with the associated CD4 count plotted as the dependent variable on the Y-axis. A Becton-Dickinson FACSCanto II flow-cytometer in Boston tested 148 healthy and immunocompromised persons with CD4% ranging from 5% to 60%. A color code was used to identify the associated absolute lymphocyte count as low (<1,200 lymphocytes/microliter light blue, 10% of samples), mid-normal (1,800 – 2,200 lymphocytes/microliter green, 25% of samples) or high (>3,700 lymphocytes/microliter red, 6% of samples).