TABLE 4.

Diagnostic Performance of Index Biomarkers (FC and FL) in Detecting Histological Disease Activity (ie, Nancy Index ≥2), With Corresponding 95% Confidence Intervals

		Nancy Index
	Cutoff	Positive ≥2	Negative ≤1	Sensitivity %*	Specificity %†	PPV %‡	NPV %§	Accuracy %║
FC	Positive >50 μg/g	82	16	57.3 [48.8–65.6]	80.7 [70.6–88.6]	83.7 [76.4–89.1]	52.3 [46.9–57.7]	65.9 [59.4–72.1]
	Negative ≤50 μg/g	61	67
	Positive >100 μg/g	58	6	40.6 [32.4–49.1]	92.8 [84.9–97.3]	90.6 [81.4–95.5]	47.5 [43.9–51.2]	59.7 [53.0–66.2]
	Negative ≤100 μg/g	85	77
FL	Positive ≥7.25 μg/g	102	29	71.3 [63.2–78.6]	65.1 [53.8–75.2]	77.9 [72.0–82.8]	56.8 [49.3–64.1]	69.0 [62.6–75.0]
	Negative <7.25 μg/g	41	54

*Sensitivity: proportion of patients correctly diagnosed as positive using the index test (TP/[TP + FN]).

†Specificity: proportion of patients correctly diagnosed as negative using the index test (TN/[TN + FP]).

‡Positive Predictive Value (PPV): proportion of patients correctly diagnosed as positive using the index test of all patients with a positive diagnosis using the index test (TP/[TP + FP]).

§Negative Predictive Value (NPV): proportion of patients correctly diagnosed as negative using the index test of all patients with a negative diagnosis using the index test (TN/[TN + FN]).

║Accuracy: proportion of patients correctly diagnosed as either positive or negative ([TP + TN]/[TP + FP + TN + FN]).

TP, true positive; TN, true negative; FP, false positive; FN, false negative.