| Signs or symptoms# required for RHC | |
| Transthoracic echocardiogram | |
| TR velocity 2.5–2.8 m·s−1 | Yes |
| TR velocity >2.8 m·s−1 | No |
| Right atrial (major dimension >53 mm) or right ventricular enlargement (mid-cavity dimension >35 mm), irrespective of TR velocity | No |
| Pulmonary function test | |
| FVC/DLCO >1.6 and/or DLCO <60% pred¶ | Yes |
| FVC/DLCO >1.6 and/or DLCO <60% pred and NT-proBNP more than twice upper limit of normal¶ | No |
| Composite measure | |
| Meets DETECT algorithm in patients with DLCO <60% pred and disease duration >3 years | No |
TR: tricuspid regurgitation; FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; % pred: % predicted; NT-proBNP: N-terminal pro-brain natriuretic peptide. #: symptoms include dyspnoea on rest or exercise, fatigue, pre-syncope/syncope, chest pain, palpitations, dizziness and light-headedness; signs include loud pulmonic sound and peripheral oedema. ¶: transthoracic echocardiogram without overt systolic dysfunction, greater than grade I diastolic dysfunction or greater than mild mitral or aortic valve disease or evidence of pulmonary hypertension. Reproduced with modification from [50] with permission from the publisher.