Table 3. Performance of NegSpA-AI on the internal, external, and prospective test sets.

Data sets	AUC	Accuracy	Sensitivity	Specificity	F1-score
Internal test set	0.878 (0.786–0.971)	86.1 (75.9–93.1)	91.1 (78.8–97.5)	81.8 (57.7–91.4)	0.891
External test set	0.870 (0.771–0.970)	83.3 (70.7–92.1)	88.0 (68.8–97.5)	80.3 (60.3–92.0)	0.830
Prospective test set	0.815 (0.714–0.915)	79.2 (68.0–86.3)	81.1 (68.0–90.6)	79.5 (55.6–87.1)	0.819

Accuracy, sensitivity, and specificity are expressed as percentages. Data in brackets are 95% confidence intervals. NegSpA-AI, an artificial intelligence tool to improve the diagnosis of axSpA in HLA-B27-negative patients; AUC, area under the curve.