Diagnostic efficacy of fecal calprotectin combined with a high-sensitivity quantitative fecal immunochemical test for colorectal tumors

Table 1 Baseline characteristics of the study participants, mean ± SD/n (%)

Characteristics	Control	Adenoma	CRC	P value
Age (years)	49.68 ± 11.67	50.15 ± 10.49	54.93 ± 8.45	0.022
Female	24 (20)	22 (18.3)	19 (15.8)	0.528
Body height (cm)	165.75 ± 6.93	167.85 ± 7.08	168.25 ± 8.92	0.463
Body weight (kg)	64.86 ± 10.48	69.05 ± 14.08	72.22 ± 14.55	0.09
Body mass index (kg/m2)	23.53 ± 3.06	24.36 ± 3.77	25.4 ± 4.09	0.099
Hypertension	11 (9.2)	12 (10)	13 (10.8)	0.888
Diabetes	3 (2.5)	3 (2.5)	4 (3.3)	0.897
Use of antithrombotic agents	2 (1.7)	1 (0.8)	1 (0.8)	0.772
Current smoking	9 (7.5)	8 (6.7)	9 (7.5)	0.952
Current drinking	5 (4.2)	14 (11.7)	19 (15.8)	0.003

CRC: Colorectal cancer.

Table 2 Diagnostic performance of fecal calprotectin across different disease groups

Disease group	Sensitivity (95%CI)	Specificity (95%CI)	PPV (95%CI)	NPV (95%CI)	LR+	LR-	AUC (95%CI)
Adenoma	50% (33.9%-66.1%)	65% (48.5%-78.8%)	58.8% (41.4%-74.5%)	56.5% (41.6%-70.6%)	1.43 (0.85-2.41)	0.77 (0.52-1.13)	0.591 (0.466-0.716)
CRC	77.5% (61.7%-88.6%)	65% (48.5%-78.8%)	68.9% (53.5%-81.2%)	74.3% (57.1%-86.8%)	2.21 (1.41-3.49)	0.35 (0.19-0.64)	0.797 (0.697-0.897)
Presence of intestinal lesions	63.8% (52.2%-74.1%)	65% (48.5%-78.8%)	78.5% (66.8%-87.2%)	47.3% (34%-61%)	1.82 (1.16-2.87)	0.56 (0.39-0.81)	0.694 (0.6-0.787)

CRC: Colorectal cancer; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; LR+: Positive likelihood ratio; LR-: Negative likelihood ratio; AUC: Area under the receiver operating characteristic curve.

Table 3 Diagnostic performance of high-sensitivity quantitative fecal immunochemical test across different disease groups

Disease group	Sensitivity (95%CI)	Specificity (95%CI)	PPV (95%CI)	NPV (95%CI)	LR+	LR-	AUC (95%CI)
Adenoma	37.5% (22.9%-54.3%)	92.5% (79.7%-98.1%)	83.3% (60.5%-95.4%)	59.7% (46.6%-71.6%)	5 (1.9-13.2)	0.68 (0.5-0.9)	0.653 (0.532-0.774)
CRC	80% (64.4%-90.5%)	92.5% (79.7%-98.1%)	91.4% (77.2%-97.8%)	82.2% (67.9%-91.5%)	10.67 (3.55-32)	0.22 (0.12-0.4)	0.872 (0.786-0.958)
Presence of intestinal lesions	58.8% (47.1%-69.7%)	92.5% (79.7%-98.1%)	94% (83%-98.6%)	52.9% (40.6%-64.9%)	7.84 (2.6-23.6)	0.45 (0.34-0.59)	0.762 (0.677-0.848)

CRC: Colorectal cancer; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; LR+: Positive likelihood ratio; LR-: Negative likelihood ratio; AUC: Area under the receiver operating characteristic curve.

Table 4 Diagnostic performance of the combined test across different disease groups

Disease group	Sensitivity (95%CI)	Specificity (95%CI)	PPV (95%CI)	NPV (95%CI)	LR+	LR-	AUC (95%CI)
Adenoma	65% (48.5%-78.8%)	60% (43.5%-75%)	61.9% (46.2%-76%)	63.2% (46.6%-77.8%)	1.63 (1.04-2.53)	0.58 (0.36-0.95)	0.662 (0.543-0.782)
CRC	87.5% (73%-95.8%)	60% (43.5%-75%)	68.6% (54.9%-80.2%)	82.8% (64.7%-93.2%)	2.19 (1.47-3.26)	0.21 (0.09-0.49)	0.866 (0.784-0.949)
Presence of intestinal lesions	76.3% (65.5%-84.7%)	60% (43.5%-75%)	79.2% (68.5%-87.2%)	55.8% (40.6%-70.2%)	1.91 (1.28-2.84)	0.4 (0.25-0.63)	0.764 (0.68-0.848)

CRC: Colorectal cancer; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; LR+: Positive likelihood ratio; LR-: Negative likelihood ratio; AUC: Area under the receiver operating characteristic curve.

Table 5 Characteristics of 5 colorectal cancer cases with false-negative stool test results

No.	Size (cm)	Stage	Location	Histology	Presenting symptoms	FC value	Hs-qFIT value	Fresh or frozen	Whether anemia
1	1 × 0.4 × 0.2	TisN0M0	Sigmoid	Moderately to well-differentiated adenocarcinoma	No symptoms	< 30	< 10	Fresh	No
2	1.5 × 1.0	TisN0M0	Ileocecum	Moderately to well-differentiated adenocarcinoma	Difficulty in defecation	< 30	< 10	Fresh	No
3	2.3 × 1.8 × 1	T2N1M0	Sigmoid	Ulcerative moderately differentiated adenocarcinoma	No symptoms	< 30	< 10	Fresh	No
4	2.2 × 2 × 1	T4N2M1	Rectum	Protruded moderately to poorly differentiated adenocarcinoma	No symptoms	< 30	< 10	Frozen	No
5	1.5	T1N0M0	Rectosigmoid	Moderately to well-differentiated adenocarcinoma	Abdominal pain	< 30	< 10	Fresh	No

FC: Fecal calprotectin; hs-qFIT: High-sensitivity quantitative fecal immunochemical test.