Table 2: Discrimination of SARD and non-SARD using ANA ELISA, anti-DFS70 CIA, and ANA/DFS70 score (ANA divided by DFS70); different cut-offs.

SARDNon-SARDSensitivitySpecificityLR+/LR−

DFS pattern#12/70 (17.1%)88/130 (67.7%)67.7% (58.9–75.6%)82.9% (72.0–90.8%)2.57/0.25
QUANTA Flash DFS70#
 Cut-off 20 CU&15/70 (21.4%)79/130 (60.8%)60.8% (51.8–69.2%)78.6% (67.1–87.5%)2.84/0.50
 Cut-off 199 CU+2/70 (2.9%)25/130 (19.2%)19.2% (12.8–27.1%)97.1% (90.1–99.7%)6.73/0.83
ANA Screen ELISA*
 Cut-off 20 units58/70 (82.9%)44/130 (33.8%)82.9% (72.0–90.8%)66.2% (57.3–74.2%)2.45/0.26
 Cut-off 60 units+42/70 (60.0%)10/130 (7.7%)60.0% (47.6–71.5%)92.3% (86.3–96.2%)7.80/0.43
 Cut-off 131.2 units+17/70 (24.3%)3/130 (2.3%)24.3% (14.8–36.0%)97.7% (93.4–99.5%)10.5/0.76
ANA/DFS70 Score*
 ANA divided by DFS70
 Cut-off 19.7 CU+
36/70 (51.4%)3/130 (2.3%)51.4% (39.2–63.6%)97.7% (93.4–99.5%)22.3/0.50

*Positive result (and LR+) considered indicative for SARD; #positive result (and LR+) considered indicative for non-SARD; & cut off values were previously established; +cutoff values were defined based on receiver operating characteristics (ROC) analysis.