Table 2. Sensitivity (sens), specificity (spe), positive predictive value (PPV), and negative predictive value (NPV), areas under the curve (AUC) and its 95% confident interval (95%CI) of access recirculation (AR) with different cutoff points in screening AVF stenosis (non-stenosis, stenosis<50%, and stenosis≥50%) against duplex doppler ultrasound (DUS)

AR cutoff points	Non-stenosis (n=193) vs. AVF<50% (n=48)							Non-stenosis (n=193) vs. AVF≥50% (n=83)
	Sens	Spec	PPV	NPV	AUC	95%CI	p-value	Sens	Spec	PPV	NPV	AUC	95%CI	p-value
≥3%	68.8	23.6	13.5	81.3	0.54	0.48–0.59	0.29	88.0	29.1	29.9	87.5	0.59	0.53–0.64	<0.01
≥4%	56.3	41.7	14.4	84.6	0.51	0.46–0.57	0.79	72.3	46.9	31.9	83.1	0.60	0.54–0.65	<0.01
≥5%	45.8	54.0	14.8	85.1	0.50	0.45–0.56	0.98	60.2	58.9	33.6	81.1	0.60	0.54–0.65	<0.01
≥6%	35.4	62.7	14.2	84.8	0.51	0.45–0.57	0.80	47.0	66.4	32.5	78.4	0.57	0.51–0.62	0.03
≥7%	33.3	72.1	17.2	86.2	0.53	0.47–0.58	0.46	34.9	73.4	31.2	76.6	0.54	0.49–0.60	0.16
≥8%	22.9	77.9	15.3	85.3	0.50	0.45–0.56	0.90	30.1	80.5	34.7	77.0	0.55	0.50–0.61	0.06
≥9%	16.7	81.2	13.3	84.9	0.51	0.46–0.57	0.71	30.1	85.5	41.7	78.0	0.58	0.52–0.63	<0.01
≥10%	16.7	83.3	14.8	85.2	0.50	0.44–0.56	1.00	22.9	85.5	35.2	76.3	0.54	0.49–0.60	0.11
≥11%	12.5	87.0	14.3	85.1	0.50	0.45–0.56	0.92	22.9	90.5	45.2	77.3	0.57	0.51–0.62	<0.01
≥12%	10.4	88.4	13.5	85.0	0.51	0.45–0.56	0.81	20.5	91.7	46.0	77.0	0.56	0.51–0.62	0.01

AVF, arteriovenous fistula.