Lymphedema Diagnosis
Lymphedema is diagnosed through a combination of clinical assessment (including the Stemmer sign and palpation for fibrosis), patient-reported symptoms, and objective measurements—with circumferential measurement serving as the standard diagnostic tool for Stage 1 or greater upper extremity lymphedema, bioimpedance analysis for subclinical/early-stage disease, and water displacement or L-Dex scores providing confirmatory thresholds. 1, 2
Clinical Assessment and Physical Examination
Begin by investigating self-reported symptoms of swelling, heaviness, and numbness, which should prompt further diagnostic evaluation. 1, 2
Perform the Stemmer sign test: Inability to pinch and lift the skin fold at the base of the second toe or finger indicates lymphedema due to dermal thickening and subcutaneous fibrosis. 2, 3
Palpate the affected area for fibrosis, pitting, and overall tissue quality. 1, 2
- Lymphedema typically presents as non-pitting in later stages due to fibrosis, whereas cardiac/venous edema remains pitting. 3
Assess for unilaterality: Lymphedema is most commonly unilateral (especially secondary forms), whereas bilateral symmetric swelling suggests cardiac, renal, or systemic causes. 3
Evaluate response to elevation and diuretics: Lymphedema does not respond to elevation or diuretics, distinguishing it from cardiac/venous edema. 3
Patient History and Risk Factors
Identify risk factors that increase suspicion for lymphedema: 2, 4
- Prior cancer treatment with surgical lymph node dissection (especially axillary dissection for breast cancer) 4
- Radiation therapy, particularly to supraclavicular lymph nodes or axilla 4
- Extent of lymph node removal (five or more nodes substantially increases risk) 4
- Recurrent infections in the affected area 4
- Congenital lymphatic abnormalities for primary lymphedema 2
- Obesity (BMI >30 kg/m²) as both a risk factor and diagnostic confounder 4
Objective Diagnostic Measurements
For Upper Extremity Lymphedema (Stage 1 or Greater)
Circumferential measurement is the standard diagnostic method. 1, 2
- Measure at standardized intervals along the limb (typically at bony landmarks). 1, 2
- A volume ratio of 1.04 or greater is indicative of upper extremity lymphedema. 1
- A calculated volume differential ≥200 mL between limbs helps rule in lymphedema, though values below 200 mL cannot rule it out. 1
For Subclinical and Early-Stage Lymphedema (Stage 0 and 1)
Bioimpedance analysis (BIA) should be used to detect lymphatic transport impairments. 1, 2
- L-Dex score >7.1 is diagnostic for breast cancer-related lymphedema when no preoperative assessment is available. 1, 2
- L-Dex score >10 above preoperative baseline measures is diagnostic when baseline data exist. 1
- If preoperative measures are available, a 5% or greater volume change from baseline above and below the elbow is diagnostic. 2
- Important caveat: In moderate to late-stage lymphedema with fibrosis, BIA may show decreasing extracellular fluid even with increased tissue volume, potentially underestimating disease severity. 1, 2
Water Displacement Volumetry
Water displacement may be used to diagnose lymphedema with volumetry >200 mL compared to the contralateral arm and with volumes >10% interlimb difference. 1, 2
Head and Neck Lymphedema
Clinical examination using the Modified Head and Neck External Lymphedema and Fibrosis assessment criteria may be used in conjunction with circumferential measurement. 1, 2
- Circumferential measurement at a single point of the upper neck (under the jawline) may be useful for assessment but has not been studied as a diagnostic test. 1
Validated Diagnostic Questionnaires
The following questionnaires assist in diagnosis of secondary upper quadrant lymphedema: 1, 2
Advanced Imaging Modalities
When clinical diagnosis is uncertain or complex cases require further characterization: 2
- Ultrasound should be used as a diagnostic tool to identify tissue changes. 1, 2
- Lymphoscintigraphy may be used to detect lymphatic system impairment and is considered the gold standard when clinical suspicion remains high despite negative physical findings. 1, 2, 3
- MRI and CT may be used as diagnostic tools in complex cases. 1, 2
- Lymphography may be used to detect lymphatic system impairment in specialized settings. 1, 2
Tools NOT Recommended for Diagnosis
The following should not be used as diagnostic tools, though some may assist in assessment: 1, 2
- Tonometry is not recommended as a diagnostic tool. 1, 2
- Perometry may be used for volume assessment but not as a diagnostic tool. 1, 2
- Tissue Dielectric Constant may be used for assessment but not as a diagnostic tool. 1, 2
- Dual-energy X-Ray Absorptiometry may be used for assessment to calculate arm volume but not as a diagnostic tool. 1
- Figure-of-8 circumferential measurement for hand lymphedema may be used for assessment but has not been studied as a diagnostic test. 1
Critical Diagnostic Pitfalls
Failing to differentiate lymphedema from other causes of edema (cardiac, venous, renal) leads to delayed diagnosis and inappropriate treatment. 3
- Do not use diuretics for lymphedema—they are ineffective and physiologically unsound, as lymphedema involves protein-rich fluid accumulation that does not respond to diuretic therapy. 3
- Bilateral pitting edema with negative Stemmer sign strongly suggests cardiac, renal, or systemic causes rather than lymphedema. 3
- Obesity complicates diagnosis by potentially causing false-positive Stemmer signs and making volumetric measurements less reliable. 2, 4
Referral and Staging
Patients with clinical symptoms or swelling suggestive of lymphedema should be referred to a therapist knowledgeable about lymphedema diagnosis and treatment, such as a physical therapist, occupational therapist, or lymphedema specialist. 2