Lymphedema Workup

Updated: Apr 18, 2023
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: William D James, MD  more...
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Approach Considerations

Analysis of blood, urine, or tissue is not needed to make the diagnosis of lymphedema. Such tests, however, help to define the underlying causes of lower extremity edema when the etiology is unclear.

Liver function, blood urea nitrogen (BUN)/creatinine levels, and urinalysis results should be checked if a renal or hepatic etiology is suspected. Specific markers should be checked if a neoplasm is suspected. The patient’s complete blood count (CBC) with differential should be checked if an infectious etiology is being considered.

Detection of early mild arm lymphedema may be facilitated by using cutaneous palpation in combination with determining the tissue dielectric constant, which evaluates local tissue water in the skin and upper subcutis, measured from fixed measurement sites. [2]

Imaging is not necessary to make the diagnosis, but it can be used to confirm it, to assess the extent of involvement, and to determine therapeutic intervention.


Imaging Studies


Plain radiographs can exclude abnormalities of the bone.

CT scanning and MRI

Computed tomography (CT) scanning and magnetic resonance imaging (MRI) have been advocated by some authors for evaluation of lymphedema. However, these tests can delineate nodal architecture at a greatly increased cost and have been found to have very few advantages over lymphoscintigraphy.

An indication for CT scanning or MRI is suspicion of malignancy, for which these tests offer the most information. In addition, MRI is useful to show lymph trunk anatomy and causes of obstructive secondary lymphedema.


Ultrasonography can be used to evaluate the lymphatic and venous systems. Volumetric and structural changes can be identified within the lymphatic system using this modality, and venous abnormalities, such as deep vein thrombosis and arteriovenous fistula, can be excluded based on ultrasonographic findings. The presence of a deep vein thrombosis is in the differential diagnosis of unilateral extremity swelling, and it may also occur concomitantly with lymphedema.


Lymphangiography is an invasive technique that can be used to evaluate the lymphatic system and its patency. Although it was once considered to be the first-line imaging modality for lymphedema, it is now rarely used because of the potential adverse effects. Specifically, this technique has been shown to cause an inflammatory reaction of the endothelium of the remaining lymphatic channels, leading to scarring, atrophy, and even luminal obliteration.

Lymphangiography has been replaced by less invasive techniques and should no longer be performed on patients with lymphedema.

Fluorescence microlymphography

Fluorescence microlymphography demonstrates a lack of microlymphatics. In this modality, a light fluorescence microscope is used following subepidermal infection of FITC-dextran 150,000 demonstrates a lack of microlymphatics. [62]


Lymphoscintigraphy is the new criterion standard for evaluation of the lymphatic system. It provides detailed visualization of the lymphatic channels without promoting further damage to them. This test can be used to define anatomy and patency, evaluate dynamics of flow and reversal of flow, and determine the severity of obstruction. [63]


Biopsy and Histology

A biopsy should be performed if the diagnosis is not clinically apparent, if areas of chronic lymphedema look suspicious, or if areas of chronic ulceration exist.

Biopsy of the skin is performed using standard techniques. A 25-gauge needle is used to infiltrate the skin with local anesthesia. The skin is stretched perpendicular to the desired line of the scar, and a punch biopsy tool is rotated into the skin to obtain a small circle of tissue. This sample is sent to pathology for histologic staining. Bleeding is controlled by the application of pressure to the area or by the use of a single suture. Topical antibiotics applied twice daily speed wound healing.

Histologic findings include hyperkeratosis with areas of parakeratosis, acanthosis, and diffuse dermal edema with dilated lymphatic spaces. In chronic lymphedema, marked fibrosis and scattered foci of inflammatory infiltrate can be seen.