Detachable string magnetically controlled capsule endoscopy for the noninvasive diagnosis of esophageal diseases: A prospective, blind clinical study

Table 1 Methods for detecting diseases in experimental and control groups

		EGD
		Positive	Negative	Total
ds-MCE	Positive	a	b	a + b (R1)
	Negative	c	d	c + d (R2)
	Total	a + c (C1)	b + d (C2)	a + b + c + d (N)

(1) Sensitivity = Number of true positives/(number of true positives + number of false negatives) × 100 = a/C1; (2) Specificity = number of true negatives/(number of true negatives + number of false positives) × 100 = d/C2; (3) Positive predictive value = number of true positives/(number of true positives + number of false positives) × 100 = a/R1; (4) Negative predictive value = number of true negatives/(number of true negatives + number of false negatives) × 100 = d/R2; And (5) Diagnostic accuracy (concordance) = (number of true positives + number of true negatives)/total number × 100 = (a + d)/ N. Based on the definitions, two-sided 95%CI were calculated for each of the above indicators. EGD: Esophagogastroduodenoscopy; ds-MCE: Detachable string magnetically controlled capsule endoscopy.