Diagnostic evaluation of the lupus band test in discoid and systemic lupus erythematosus.

BACKGROUND: The usefulness of the lupus band test (LBT) in the diagnosis of cutaneous lupus erythematosus remains controversial. The study was done to determine the sensitivity, specificity, and predictive value of the LBT in discoid lupus erythematosus (DLE) and systemic lupus erythematosus (SLE).

METHODS: During the study period, 32 patients with SLE and 28 patients with DLE were included. The final classification of cases was based on the American Rheumatism Association Criteria (ARA) for SLE, histopathology, and consensus of the clinical staff. Thirty controls, 15 each for DLE and SLE, were chosen from a group of patients, who had lesions clinically simulating DLE and SLE, but could be excluded by histopathology, laboratory tests, and follow-up. Histopathologic examinations and direct immunofluorescence (DIF) tests were done on lesional skin.

RESULTS: In DLE, the sensitivity of the LE band test was 58% and the specificity 87%. The positive predictive value was 95% and negative predictive value was 32%. In SLE the sensitivity was 93% and specificity 87%. The positive predictive value was 64% and negative predictive value 98%.

CONCLUSIONS: The high negative predictive value of LBT in SLE suggests that it is valuable in excluding diseases clinically similar to SLE.