Table 4.

Summary Statistics for the Diagnostic Accuracy of ¹³C-Urea Breath Test.

Sub-groups	Number of Studies	P-value (I2)a	P-value (I2)b	Sensitivity (95% CI)	Specificity (95% CI)
All studies*	15	<0.01 (72.8%)	<0.01 (64.5%)	0.97 (0.96, 0.98)	0.96 (0.95, 0.97)
By dose of 13C-urea**
50 mg	4	0.24# (28.7%)	0.17# (40.6%)	1.00 (0.98, 1.00)	0.99 (0.96, 1.00)
75 mg	4	0.01 (76.5%)	0.28# (21.0%)	0.93 (0.90, 0.96)	0.96 (0.94, 0.98)
100 mg	5	0.07 (53.0%)	<0.01 (76.1%)	0.98 (0.97, 0.99)	0.94 (0.92, 0.96)
By cut-off threshold
<5.0 δ over baseline	9	0.02 (54.4%)	<0.01 (75.9%)	0.98 (0.97, 0.99)	0.96 (0.95, 0.97)
≥5.0 δ over baseline	6	<0.01 (76.5%)	0.30# (17.3%)	0.94 (0.92, 0.96)	0.97 (0.95, 0.98)
By breath sample collection time
10 to 15 minutes	5	<0.01 (83.0%)	0.06 (55.4%)	0.96 (0.94, 0.98)	0.94 (0.90, 0.96)
20 minutes	5	0.26# (24.0%)	0.15# (40.3%)	0.99 (0.98, 1.00)	0.99 (0.97, 1.00)
30 minutes	5	0.07 (54.6%)	0.10# (48.4%)	0.96 (0.94, 0.97)	0.96 (0.94, 0.98)
By locality***
Hong Kong	6	<0.01 (75.5%)	0.36# (8.4%)	0.96 (0.94, 0.98)	0.98 (0.96, 0.99)
Taiwan	5	0.13# (44.0%)	0.06 (54.8%)	0.98 (0.96, 0.99)	0.93 (0.91, 0.96)
By manufacturer
13C-UBT (INER, Taiwan)	5	0.13# (44.0%)	0.06 (54.8%)	0.98 (0.96, 0.99)	0.93 (0.91, 0.96)
Others	10	<0.01 (77.5%)	0.05 (46.7%)	0.96 (0.94, 0.97)	0.98 (0.97, 0.99)

* Four articles had data for two sets of samples, tools and findings; a total of 15 studies were obtained.

** One study was not included in this sub-group due to absence of reported ¹³C-urea amount used, and another study was excluded due to use of multiple amounts in a single study (for different age groups in children).

*** Studies done in Japan, Israel and Singapore were excluded due to having only two or less studies per locality.

^a P-value for heterogeneity (chi-squared) and I² test for heterogeneity quantification for sensitivity analysis.

^b P-value for heterogeneity (chi-squared) and I² test for heterogeneity quantification for specificity analysis.

_# P-value is not significant (≥0.1).