Diagnostic components for idiopathic pulmonary fibrosis (IPF)
| ATS/ERS/JRS/ALAT clinical practice guideline [1] | Fleischner white paper consensus statement [2] | |
| Age limit for increased diagnostic confidence | 60 years | |
| HRCT pattern | UIP | Typical UIP |
| Subpleural and basal predominance | ||
| Presence of honeycombing with or without peripheral traction bronchiectasis | ||
| Biopsy not recommended | ||
| Probable UIP | ||
| Subpleural and basal predominance | ||
| Presence of peripheral traction bronchiectasis | ||
| Biopsy recommended (conditional) | Biopsy not recommended | |
| Indeterminate for UIP | ||
| Subpleural and basal predominant | Variable or diffuse | |
| May have mild GGO or distortion | Features suggestive of non-UIP pattern | |
| Biopsy recommended | ||
| Alternative diagnosis | Most consistent with non-IPF diagnosis | |
| Findings suggestive of another diagnosis | ||
| Biopsy recommended | ||
| Histopathology pattern | UIP | Definite UIP |
| Dense fibrosis with architecture remodelling | ||
| Predominant subpleural or paraseptal distribution of fibrosis | ||
| Patchy lung involvement by fibrosis | ||
| Presence of fibroblastic foci | ||
| Probable UIP | ||
| Honeycomb fibrosis only | ||
| Fibroblastic foci may or may not be present | ||
| Indeterminate for UIP | ||
| Fibrosis with or without architecture distortion Some histological features from the UIP pattern | Occasional foci of centrilobular injury or scarring Rare granulomas or giant cells Minor degree of lymphoid hyperplasia or diffuse inflammation Diffuse homogenous fibrosis favouring fibrotic nonspecific interstitial pneumonia | |
| Alternative diagnosis | Features most consistent with an alternative diagnosis | |
| Histological findings indicative of other diseases | A UIP pattern with ancillary features strongly suggesting an alternative diagnosis A non-UIP pattern | |
Criteria have been summarised for purposes of comparison. ATS: American Thoracic Society; ERS: European Respiratory Society; JRS: Japanese Respiratory Society; ALAT: Latin American Thoracic Society; HRCT: high-resolution computed tomography; UIP: usual interstitial pneumonia; GGO: ground-glass opacities.