The Imp™ XCA is a low frequency impedance analyzer designed to assist in the clinical assessment of unilateral lymphedema of the arm. The Imp™ XCA utilizes a simple linear scale called the L-Dex (lymphedema index). The L-Dex ranges from -10 to +10 and defines the normal range of L-Dex values for a patient without lymphedema. The presence or absence of lymphedema is assessed by comparing the patientŐs L-Dex to this range.