The L-Dex ratio correlated with limb volume and clinical assessment of pitting edema, and physiologic measures of lymphatic function, and demonstrated face, construct, and criterion validity in response to intervention. These findings support the adjunctive use of the L-Dex ratio with limb volume measurements for objective diagnosis, evaluation of lymphedema severity, longitudinal serial evaluation of lymphedema, and response to conservative and surgical interventions. Open access: No View