Non-guided self-learning program for high-proficiency optical diagnosis of diminutive and small colorectal lesions: A single-endoscopist pilot study

Table 4 Overall diagnostic performance of narrow band imaging and the Narrow Band Imagig International Colorectal Endoscopic classification system

Parameter	High-confidence		Low-confidence
	1-5 mm, n = 347	6-9 mm, n = 115	1-5 mm, n = 51	6-9 mm1, n = 7
Sensitivity	97.0 (95.2-98.8)	100.0	76.0 (64.3-87.7)	N/A
Specificity	74.3 (69.4-78.6)	94.4 (90.2-98.6)	46.1 (32.4-59.8)	57.1 (20.4-57.1)
PPV	88.5 (84.6-91.4)	99.0 (97.2-100.0)	57.6 (44.0-71.2)	0
NPV	92.3(89.1-94.8)	100.0	66.7 (53.8-79.6)	100.0
LR+	3.8 (1.2-4.8)	18.0 (10.1-23.9)	1.4 (-1.8-4.6)	N/A
Accuracy	89.5 (85.7-92.3)	99.1 (97.4-100.0)	60.7 (47.3-74.1)	57.1 (20.4-57.1)

Data are given as % (95%CI).

¹No adenoma was diagnosed with low-confidence.

CI: Confidence interval; LR: Likelihood ratio; N/A: Non-applicable; NPV: Negative predictive value; PPV: Positive predictive value.