Table 4.

Concordance of PIK3CA mutation status between endoscopic biopsy and surgically resected specimens

		Surgically resected specimens (reference method)
		Wild type	Mutant type	Total
Endoscopic biopsy specimens (trial method)	Wild type	168	2	170
	Mutant type	1	10	11
	Total	169	12	181
Overall concordance rate		98.3% (95% CI: 95.2–99.7)
Positive concordance rate		83.3% (95% CI: 51.6–97.9)
Negative concordance rate		99.4% (95% CI: 96.7–99.9)
Positive predictive value		90.9% (95% CI: 58.7–99.8)
Negative predictive value		98.8% (95% CI: 95.8–99.9)

Abbreviations: CI confidence interval