Validation of the Spanish version of a screening questionnaire for the detection of systemic lupus erythematosus.

The aim of this study was to assess the sensitivity, specificity, positive and negative predictive values of the translation of a screening questionnaire for systemic lupus erythematosus (SLE) in Spanish-speaking populations. The questionnaire was applied to secondary-care outpatients in a rheumatology clinic. Sensitivity, specificity, predictive positive and negative values of the instrument, and the best cut-off point to discriminate between SLE patients and other conditions, were determined. Fifty-two subjects answered the questionnaire (21 patients with SLE, 15 with a possible diagnosis of SLE who eventually proved not to have the disease, and 16 healthy volunteers), which can be answered in 2 min. The best cut-off point was three affirmative answers (95% specificity, 84% sensitivity, 80% predictive positive and 96% predictive negative values). The questionnaire can discriminate between SLE cases and other conditions. Sensitivity and specificity are close to those of the original English version. Applying this instrument can help to acquire informed estimates of SLE prevalence.