Introduction
Lymphoedema is a chronic, progressive condition where the accumulation of excessive amounts of protein-rich fluid within the tissues results in swelling of one or more regions of the body. This occurs due to a damaged or compromised lymphatic system where the demand for lymphatic drainage exceeds the capacity of the lymphatic circulation. Lymphoedema has many possible causes including congenital abnormalities, cancer treatment, chronic venous disease and immobility.
The good news is that early detection, monitoring and intervention can make a huge difference in limiting lymphoedema progression, preventing complications and supporting long-term condition management. Where traditional assessment methods (like tape measurements) can only detect lymphoedema once it has already developed clinical signs and symptoms, bioimpedance spectroscopy (BIS), a groundbreaking technological advancement in the early detection of lymphoedema, can detect lymphatic system changes as early as the sub-clinical stage, before swelling becomes observable.
In this blog article, we explore BIS and the SOZO device, the gold-standard BIS unit that we use in our Newcastle clinic.
What is Bioimpedance Spectroscopy (BIS)?
Bioimpedance spectroscopy (BIS) is an advanced, non‑invasive technology that uses electrical currents passing through the body to accurately measure fluid distribution and body composition. This detailed data can help clinicians with early detection, assessment and intervention for lymphoedema.
Unlike traditional assessment methods (like tape measurements or scales), BIS can detect changes in fluid levels before swelling in visible, identifying early lymphatic system changes that may signal the onset of lymphoedema. BIS provides objective, quantitative data that clinicians can use to track trends over time and make informed decisions about prevention and management.
What is the ‘SOZO’?
The SOZO® Digital Health Platform, created by ImpediMed, is a device that uses BIS technology to provide clinicians with a rapid and comprehensive view of a patient’s fluid status and body composition. The device delivers in‑clinic results in under 30 seconds without invasive procedures.
The SOZO measures fluid and tissue data, including:
- L‑Dex® score — an indicator of limb fluid asymmetry associated with lymphoedema
- Intracellular (ICF) and extracellular (ECF) fluid levels
- Total body water (TBW)
- Phase angle — a broader marker of cellular health
- Body composition metrics like skeletal muscle and fat mass
- Basal Metabolic Rate (BMR)
- BMI and segmental limb analysis
This combination of data allows for precise tracking of physical changes throughout the care journey.
What Happens During a SOZO Scan
A SOZO scan is designed to be simple, comfortable, and quick, but there are a few steps your clinician will take to ensure the data is accurate and useful.
1. Preparation Before the Scan
Before your SOZO measurement begins, your clinician will:
- Ask you to remove metal jewellery and electronic items (rings, watches, keys) as metal can interfere with the electrical signals
- Remove shoes, socks, stockings or pantyhose, so your bare feet can rest directly on the electrodes
- Wipe or dampen your hands and feet if needed — this improves contact between your skin and the electrodes for a high‑quality reading
- Enter or confirm your height and weight in the system — height and weight is used in body composition calculations and helps improve the accuracy of results
2. Positioning of the Device
Once you’re ready, the SOZO device is used like this:
- You stand with your feet placed on the foot electrodes (metal plates)
- You place both hands on the hand electrodes, wrapping your palms gently around the metal plates so there is firm, full contact
- Your clinician will start the scan from the tablet or interface
This positioning lets the system send a low‑level, safe electrical signal through your body so it can measure how resistance and reactance vary across different tissues, building a picture of fluid and body composition.
Important: The signal used is imperceptible – you can’t feel it and there’s no pain or discomfort during the test.
3. The Scan Itself — What Happens Next
Once everything is in place:
- The SOZO device takes a measurement that lasts about 30 seconds
- You simply stand on the device while the scan happens
During this time, the SOZO rapidly collects data at 256 different electrical frequencies. This provides much more detailed information compared to the commonly used single‑frequency body analysers.
All of this happens while you’re simply standing with no needles, gels, clamps or attachments.
4. Reviewing Your Results
Immediately after the scan:
- Your clinician will see your results on the tablet screen
- Results can also be uploaded into a cloud‑based record system so that results can be tracked over time and compared to previous scans
- Your clinician can explain what the numbers mean, for example:
- If your L‑Dex® score is higher than expected, that might indicate early lymphatic system changes
- If the body composition outputs change over time, this might help guide your rehabilitation plan, exercise goals, or hydration recommendations
You can get feedback right away, and your clinician can use these objective results to:
- Adjust your therapy plan
- Monitor trends without waiting for observable symptoms
- Motivate you with measurable progress
What is an 'L-Dex Score'?
The L‑Dex® score is one of the most important parts of a SOZO scan when it comes to lymphoedema monitoring. It measures how much fluid is in a limb compared to a healthy baseline. Because the SOZO detects changes when they are still subtle (as little as 2 tablespoons difference), this can give your clinician time to intervene before swelling becomes more significant.
Here’s how it helps:
✔ Establishes a baseline before treatment begins
✔ Tracks fluid changes over time
✔ Alerts clinicians to early lymphatic system changes
✔ Allows earlier, more effective intervention
Normal L‑Dex scores fall within a specific range, and changes beyond that range can indicate early lymphatic system changes, even if you don’t feel any different.
Why is Early Detection So Important?
Lymphoedema is a common side effect following cancer treatment that involves surgery, lymph node removal, radiation therapy and/or chemotherapy — affecting up to 58% of at‑risk patients depending on treatment type.
Traditionally, lymphoedema is diagnosed only after noticeable swelling or limb size changes occur. By then, the condition may have already progressed to a chronic stage where it can become more difficult to manage. BIS changes this by enabling:
- Sub-clinical detection of lymphoedema (before visible swelling is present)
- Objective quantification of fluid changes
- Trend tracking over time to guide early intervention
This means more chances to stop lymphoedema before it becomes a long‑term issue.
The Use of BIS in Lipoedema Monitoring
Lipoedema is a chronic connective tissue disorder characterised by painful, disproportionate fat tissue accumulation, often misdiagnosed as obesity or lymphoedema. The SOZO supports personalised treatment strategies in lipoedema management that are much more precise than standard methods like scales or tape measures alone. In lipoedema, the SOZO’s BIS readings can help clinicians:
- Distinguish between fluid levels and fatty tissue accumulation
- Track limb changes over time
- Personalise therapy plans, including compression, exercise, and education
This differentiation empowers more targeted and effective care strategies.
Integrating the SOZO at Hunter Rehab Hub
Hunter Rehab Hub is one of very few providers of the SOZO technology in the region, servicing patients across Newcastle, Lake Macquarie, Maitland, Port Stephens and the Hunter Valley.
At Hunter Rehab Hub, SOZO assessments are integrated into our comprehensive assessment services to provide:
✔ Baseline measurements before treatment begins
✔ Regular surveillance throughout the rehabilitation journey
✔ Early intervention when fluid changes are detected
✔ Monitoring of therapy effectiveness
This approach helps patients stay ahead of complications, can improve functional outcomes, and enhance quality of life.
In Summary
Bioimpedance spectroscopy, delivered via the SOZO device, brings precision and foresight to lymphoedema monitoring. With early detection and objective tracking, it allows clinicians to act sooner, customise care more effectively, and limit long‑term complications.
If you’d like to learn how a SOZO scan could form part of your management plan, contact our team on 0480 604 578 or book a SOZO scan online using the button below.
References
Australian Lymphoedema Education, Research and Treatment Centre. (2025). Bioimpedance spectroscopy in lymphoedema assessment and surveillance. Macquarie University, Sydney.
Australian Lymphology Association. (2022). Best practice guidelines for lymphoedema management in Australia.
Cancer Institute NSW. (2023). Lymphoedema after cancer treatment: Information for patients and clinicians.
ImpediMed. (2024). SOZO® Digital Health Platform: Clinical applications of BIS and L-Dex®.
Koelmeyer LA, et al. (2025). Assessment of bilateral lower limb lymphoedema using bioimpedance spectroscopy. Disability and Rehabilitation.
Ward LC, et al. (2009). Bioimpedance spectroscopy for early detection of lymphoedema. Lymphatic Research and Biology, 7(2), 113–117.
Disclaimer
This content is general in nature and provided for educational purposes only. It is not a substitute for individualised medical advice, diagnosis, or treatment. If you have concerns about swelling or your health, consult a qualified healthcare professional.
