Utility of age, gender, ANA titer and pattern as predictors of anti-ENA and -dsDNA antibodies.

Monovariate and multivariate analyses including logistic regression were performed to determine associations among predicting variables [age, gender, immunofluorescence pattern, and anti-nuclear antibody (ANA) titer] and anti-extractable nuclear antigen (ENA) and -dsDNA antibodies (Abs) in 1089 patients with positive fluorescent ANA (FANA) test results. Samples with high titer ANAs had an increased frequency of anti-ENA and -dsDNA Abs. The receiver operating (ROC) curves of the ANA titer for anti-ENA Abs had a larger under the curve area compared to the ROC curve for anti-dsDNA Abs, indicating that ANA titer is better for predicting anti-ENA Abs than anti-dsDNA Abs.