ISL Lymphedema Staging (Stage and Volume Severity)
The International Society of Lymphology staging of peripheral lymphedema (2020 Consensus Document).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- The stage, describing what the tissue has become
- More changes in solid structures.
- Severity by excess volume difference between limbs
- Excess volume of 20 to 40 percent.
- Is the swelling bilateral?
- Yes
Result: ISL Stage II, moderate by volume.
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What the result means
- Stage 0
- Latent. Swelling not yet evident despite impaired lymph transport; may precede overt edema by months or years.
- Stage I
- Protein-rich fluid that subsides with limb elevation. Pitting may occur.
- Stage II
- Elevation alone rarely reduces the swelling, and pitting is manifest.
- Late stage II
- The limb may not pit as fat and fibrosis develop. That is fibrosis, not improvement.
- Stage III
- Lymphostatic elephantiasis with trophic skin changes. Pitting can be absent.
- Severity
- A separate axis by excess volume: minimal above 5 to below 20 percent, moderate 20 to 40, severe above 40. Bilateral swelling understates it.
What you enter
- The stage, describing what the tissue has become
- Severity by excess volume difference between limbs - a SEPARATE axis from the stage
- Is the swelling bilateral?
Full field descriptions
- The stage, describing what the tissue has become [0 = Stage 0 (latent or subclinical): Swelling is not yet evident despite impaired lymph transport, with subtle alterations in tissue fluid and composition and changes in subjective symptoms. Not applicable. Not applicable: there is no overt edema to pit. I = Stage I: An early accumulation of fluid relatively high in protein content. The swelling SUBSIDES with limb elevation. Pitting MAY occur. II = Stage II: More changes in solid structures. Limb elevation alone RARELY reduces the tissue swelling. Pitting IS manifest. late II = Late stage II: Excess subcutaneous fat and fibrosis develop. Elevation does not reduce the swelling. The limb MAY NOT pit. That is fibrosis replacing fluid, not improvement. III = Stage III: Lymphostatic elephantiasis, with trophic skin changes such as acanthosis, alterations in skin character and thickness, further deposition of fat and fibrosis, and warty overgrowths. Elevation does not reduce the swelling. Pitting CAN BE ABSENT. Again, that is fibrosis, not improvement.]
- Severity by excess volume difference between limbs - a SEPARATE axis from the stage [none = Not graded, Excess volume at or below 5 percent. Subclinical lymphedema is measurable from about 3 to 5 percent, which sits below the minimal grade, so a limb can be measurably abnormal and still ungraded. minimal = Minimal, Excess volume above 5 percent and below 20 percent. moderate = Moderate, Excess volume of 20 to 40 percent. severe = Severe, Excess volume above 40 percent.]
- Is the swelling bilateral? Required, because the severity grade is an inter-limb comparison and bilateral swelling understates the disease.
How this is calculated
International Society of Lymphology. The diagnosis and treatment of peripheral lymphedema: 2020 Consensus Document of the International Society of Lymphology. Lymphology. 2020;53(1):3-19. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.