To differentiate acute purulent tonsillitis from infectious mononucleosis, divide the total number of lymphocytes by the WBC count. If the ratio is >0.35, the diagnosis is mono. One of our biggest insurers will not pay for a rapid mono test, and this is much more efficient than waiting for an Epstein-Barr virus titer. I have tested this method 10 times, and it has proven 100% accurate. For additional information, see Arch Otolaryngol Head Neck Surg. 2007;133:61-64.
—William Stoecklin, RPA-C, Albany, N.Y. (117-26)