L-Dex® Score

ImpediMed devices incorporate L-Dex technology and bioimpedance spectroscopy (BIS) to measure and monitor fluid status—non-invasively, easily, quickly and accurately. The L-Dex score represents the difference in the amount of extracellular fluid in an at-risk limb compared to an unaffected limb.

L-DEX value

How it works

Using BIS technology, the ImpediMed device sends a low-level electrical signal through the body. As lymphedema develops, the amount of fluid will increase, making it easier for the signal to travel though the extracellular fluid of the body.

The L-Dex score compares how easily the electrical signal moves through the unaffected and the affected limbs. The L-Dex score is initially displayed against a normal or healthy range, as shown. For patients with a baseline measurement, subsequent L-Dex scores can be compared to their baseline for an even more personalized assessment. At-risk patients receive a baseline measurement before treatment and then are measured regularly after treatment. An L-Dex increase of 6.5 or more is an indication that lymphedema is developing, and intervention is needed.

L-Dex in clinical practice

Lymphedema is rarely diagnosed until the patient experiences symptoms like pain, tightness, or swelling in their limb. However, with early diagnosis and ongoing monitoring, the condition can be well managed.1-3 By identifying the patient’s baseline L-Dex score before cancer treatment and then measuring it at regular intervals post-surgery, healthcare professionals can accurately monitor patient progress and offer appropriate education and intervention to prevent the progression of lymphedema. Recently published interim results from the PREVENT Trial showed that this early detection combined with at-home intervention using standard compression therapy can reduce the progression of lymphedema by 95%.4


SOZO, the world’s most advanced, noninvasive BIS device, incorporates L-Dex technology to deliver a precise snapshot of fluid status and tissue composition in less than 30 seconds. SOZO aids in the early detection of secondary lymphedema and provides fluid status for patients living with heart failure.

Clinical evidence

ImpediMed’s BIS technology has been extensively studied in over 40 medical conditions and disease states.


  1. Hayes S, Cornish B, Newman B. Comparison of methods to diagnose lymphedema among breast cancer survivors: 6-month follow up. Breast Cancer Res Treat. February 1989;(3):221-226.
  2. Czerniec S, et al. Assessment of lymphedema using measurement tools and self-report. 7th National Lymphedema Network Conference; 2006; Nashville, TN, USA.
  3. Cornish BH, et al. Early diagnosis of lymphedema using multiple frequency bioimpedance. Lymphology. 2001;34:2-11.
  4. Ridner SH, et al. A randomized trial evaluating bioimpedance spectroscopy versus tape measurement for the prevention of lymphedema following treatment for breast cancer: interim analysis. Ann Surg Oncol 2019; https://doi.org/10.1245/s10434-019-07344-5.
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