Level II study of screening tests for pulmonary arteriovenous malformations (PAVMs) in patients with hereditary haemorrhagic telangiectasia (HHT), using reference standard
| Study | No of subjects | Prevalence of PAVMs | Reference standard | Test | Sensitivity | Specificity |
| Cottin et al (2004)82 | 105 | 45% | CT or PA | TTCE | 93% | 52% |
| Chest x-ray | 70% | 98% | ||||
| A-a gradient | 68% | 98% |
A-a gradient, alveolar–arterial gradient calculated from arterial blood gas on room air; CT, CT of the chest; PA, diagnostic pulmonary angiography; TTCE, transthoracic contrast echocardiography (using agitated saline).