Table 1.
Mean DOB, sensitivities, specificities, positive and negative predictive values, and accuracies of 13C-UBT with or without citric acid.
| Without citric acid (n = 189) | Low-dose citric acid (n = 189) | P value | Without citric acid (n = 96) | High-dose citric acid (n = 96) | P value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Self-control* (30 min) | 15 min | 30 min | Self-control vs. 15 min | Self-control vs. 30 min | 15 min vs. 30 min | Self-control* (30 min) | 15 min | 30 min | Self-control vs. 15 min | Self-control vs. 30 min | 15 min vs. 30 min | |
| DOB (+) (mean ± SD) | 24.00 ± 15.21 | 41.18 ± 27.11 | 36.05 ± 21.71 | < 0.0001 | < 0.0001 | 0.001 | 25.44 ± 16.38 | 49.05 ± 25.50 | 47.66 ± 19.95 | < 0.0001 | < 0.0001 | 0.898 |
| DOB (−) (mean ± SD) | 2.11 ± 8.69 | 0.79 ± 2.40 | 0.89 ± 2.38 | 0.495 | 0.573 | 0.239 | 1.22 ± 2.22 | 0.44 ± 0.36 | 0.90 ± 0.83 | 0.129 | 0.674 | 0.002 |
| Sensitivity (%) | 99.1 (107/108) | 99.1 (107/108) | 99.1 (107/108) | > 0.999 | > 0.999 | > 0.999 | 100.0 (53/53) | 100.0 (53/53) | 100.0 (53/53) | > 0.999 | > 0.999 | > 0.999 |
| Specificity (%) | 88.9 (72/81) | 97.5 (79/81) | 97.5 (79/81) | 0.056 | 0.056 | > 0.999 | 88.4 (38/43) | 100.0 (43/43) | 100.0 (43/43) | 0.055 | 0.055 | > 0.999 |
| PPV (%) | 92.2 (107/116) | 98.2 (107/109) | 98.2 (107/109) | 0.060 | 0.060 | > 0.999 | 91.4 (53/58) | 100.0 (53/53) | 100.0 (53/53) | 0.058 | 0.058 | > 0.999 |
| NPV (%) | 98.6 (72/73) | 98.8 (79/80) | 98.8 (79/80) | > 0.999 | > 0.999 | > 0.999 | 100.0 (38/38) | 100.0 (43/43) | 100.0 (43/43) | > 0.999 | > 0.999 | > 0.999 |
| Accuracy (%) | 94.7 (179/189) | 98.4 (186/189) | 98.4 (186/189) | 0.087 | 0.087 | > 0.999 | 94.8 (91/96) | 100.0 (96/96) | 100.0 (96/96) | 0.059 | 0.059 | > 0.999 |
*(Self-control 30 min): commercial 13C-UBT that breath samples were taken at 30 min without citric acid.
(+): H. pylori status gold standard positive; (−): H. pylori status gold standard negative.