Diagnostic characteristics for the hypoxia-altitude simulation test (HAST) to predict altitude-related adverse health effects (ARAHE) in patients with COPD travelling to 3100 m
| SpO2 criterion | Positive | Negative | Total |
| ARAHE | 50 | 25 | 75 |
| HAST | 27 | 48 | 75 |
| ARAHE positive | ARAHE negative | ||
| HAST by SpO2 positive | 23 TP | 4 FP | 27 |
| HAST by SpO2 negative | 27 FN | 21 TN | 48 |
| Total patients | 50 | 25 | 75 |
| PaO2 criterion | Positive | Negative | Total |
| ARAHE | 44 | 20 | 64 |
| HAST | 12 | 52 | 64 |
| ARAHE positive | ARAHE negative | Total patients | |
| HAST by PaO2 positive | 11 TP | 1 FP | 12 |
| HAST by PaO2 negative | 33 FN | 19 TN | 52 |
| Total patients | 44 | 20 | 64 |
Cut-off values for a positive HAST are set as SpO2 <85% and/or PaO2 <6.6 kPa according to the British Thoracic Society (BTS). Positive ARAHE is defined as development of acute mountain sickness, need of oxygen therapy due to severe hypoxaemia (resting SpO2 <80% >30 min or <75% for >15 min) or any other intercurrent illness needing treatment such as chest pain, severe dyspnoea, arrhythmia, hypertensive crisis or others (see text). SpO2: oxygen saturation measured by pulse oximetry; PaO2: arterial oxygen tension; TP: true positive; FP: false positive; FN: false negative; TN: true negative.