Faecal immunochemical tests for the diagnosis of symptomatic colorectal cancer in primary care: the benefit of more than one sample

Figures & data

Figure 1. Selection of the study group, starting with 538 patients. ¹(colorectal cancer + adenomas with high-grade dysplasia). FIT: faecal immunochemical test.

Table 1. The number of positive samples for each faecal immunochemical test (FIT) in symptomatic patients diagnosed with colorectal cancer or adenomas with high grade dysplasia (HGD).

		Number of positive samples.Total (adenomas HGD).
		0	1	2	3	4	5	6
FITs with 1 sample	N = 8	2	6
FITs with 2 samples	N = 13	1	2	10 (1)
FITs with 3 samples	N = 160	21 (2)	12 (4)	15 (2)	112 (7)
FITs with 4 samples	N = 4	1	1	1	0	1
FITs with 5 samples	N = 2	0	0	0	0	0	2 (1)
FITs with 6 samples	N = 8	0	0	1	1	1	0	5
Total	N = 195	25 (2)	21 (4)	27 (3)	113 (7)	2	2 (1)	5

Table 2. The likelihood of receiving at least one positive sample of a three-sample faecal immunochemical test (FIT), with different numbers of samples analysed, in patients with colorectal cancer or adenomas with high-grade dysplasia and 95% confidence intervals.

	Using all cases (n = 160)	Using only positive cases (n = 139)
One sample analysed	0.79 (0.72–0.85)	0.91 (0.85–0.95)
Two samples analysed	0.84 (0.78–0.89)	0.97 (0.93–0.99)
Three samples analysed	0.87 (0.81–0.91)	1.00 (0.98–1.00)