Probability and safety of decision outcomes of the pH test
| Outcome | Probability | Score |
| Feeding into the stomach by pH | Prior probability of stomach×Sensitivity of pH | 100 |
| Feeding into the lung by pH (feeding error) | Prior probability of lung×(1—Specificity in lung) | 0 |
| Feeding into the oesophagus by pH (feeding error) | Prior probability of oesophageal×(1—Specificity in oesophagus) | 45 |
| Delayed feeding into the stomach by X-rays (unnecessary X-rays) | Prior probability of stomach×(1—Sensitivity of pH) | 85 |
| No feeding outside the stomach by pH or by X-rays | Prior probability of lung/oesophagus×Specificity in lung/oesophagus | 100 |