Table 1. Comparison of the diagnostic performance in detecting recurrence of a rise in blood CEA level above a threshold of 5μg/L in relation to i) all CEA measurements taken prior to diagnosis of recurrence and ii) the final CEA measurement taken prior to diagnosis of recurrence.

	Final CEA measurement (95% CI)	All CEA measurements (95% CI)
Sensitivity	49.0% (39.2–59.0%)	50.0% (40.1–59.9%)
Specificity	97.5% (95.5–98.6%)	93.3% (90.6–95.3%)
Positive predictive value	81.0% (68.7–89.4%)	61.9% (50.6–72.1%)
Negative predictive value	89.8% (86.8–92.2%)	89.6% (86.5–92.0%)
Positive likelihood ratio	19.5 (10.8–35.3)	7.5 (5.1–11.0)
Negative likelihood ratio	0.52 (0.43–0.63)	0.54 (0.44–0.65)