The lupus band test in systemic lupus erythematosus patients.

The lupus band test (LBT) is a diagnostic procedure that is used to detect deposits of immunoglobulins and complement components along the dermoepidermal junction in patients with lupus erythematosus (LE). The LBT is positive in about 70%-80% of sun-exposed non-lesional skin specimens obtained from patients with systemic LE (SLE), and in about 55% of SLE cases if sun-protected nonlesional skin is analyzed. In patients with cutaneous LE only, the lesional skin usually shows a positive LBT. The LBT helps in differentiating LE from other similar skin conditions and may also be helpful in making the diagnosis of SLE in subjects with no specific cutaneous lesions. Furthermore, a positive LBT may be applied as a prognostic parameter for LE patients. However, the correct interpretation of this test requires detailed knowledge of the site of the biopsy, deposit components, morphology and brightness of the immunofluorescent band, and other associated serologic findings, as well as the response to treatment. It must be emphasized that LBT is a laboratory procedure that should always be interpreted in conjunction with clinical findings and other serological and immunopathological parameters.