Immunofluorescent skin band test in the differential diagnosis of systemic lupus erythematosus.

Forty-four uninvolved skin biopsies from lupus patients and 43 with various connective tissue diseases and nephritides other than lupus were tested for the presence of immunoglobulin deposition in the dermal-epidermal junction. Results were examined to determine their relationship to renal and clinical activity. Lupus band test (LBT) was positive in 30 (60%) SLE patients regardless of renal or clinical status. DNA-binding (p less than 0.01) and ANA (p less than 0.002) correlated to LBT. None of the other nephritides and only 2 with other connective tissue diseases were positive. LBT is a good aid in the differential diagnosis of SLE regardless of clinical or renal activity.