Diagnostic Accuracy of Lymphoscintigraphy for Lymphedema and Analysis of False-Negative Tests

Lymphedema is the chronic enlargement of tissue due to inadequate lymphatic function. Diagnosis is made by history and physical examination and confirmed with lymphoscintigraphy. The purpose of this study was to assess the accuracy of lymphoscintigraphy for the diagnosis of lymphedema and to determine characteristics of patients with false-negative tests. METHODS Individuals referred to our lymphedema program with "lymphedema" between 2009 and 2016 were analyzed. Subjects were assessed by history, physical examination, and lymphoscintigraphy. Patient age at presentation, duration of lymphedema, location of disease, gender, previous infections, and lymphedema type were analyzed. RESULTS The study included 227 patients (454 limbs); lymphedema was diagnosed clinically in 169 subjects and confirmed by lymphoscintigraphy in 162 (117 primary, 45 secondary; 96% sensitivity). Fifty-eight patients were thought to have a condition other than lymphedema, and all had negative lymphoscintigrams (100% specificity). A subgroup analysis of the 7 individuals with lymphedema clinically, but normal lymphoscintigrams, showed that all had primary lymphedema; duration of disease and infection history were not different between true-positive and false-negative lymphoscintigram results (P = 0.5). Two patients with a false-negative test underwent repeat lymphoscintigraphy, which then showed lymphatic dysfunction consistent with lymphedema. CONCLUSION Lymphoscintigraphy is very sensitive and specific for lymphedema. All patients with false-negative studies had primary lymphedema. A patient with a high clinical suspicion of lymphedema and a normal lymphoscintigram should be treated conservatively for the disease and undergo repeat lymphoscintigraphy.