Chest radiograph classification at the time of serum sampling (disease onset or ≥2 yrs after diagnosis)
| Chest radiograph | Disease onset | Disease ≥2 yrs | |
| Acute onset (Löfgren's syndrome) | Insidious onset | ||
| Stage 0 | 0 | 0 | 1 |
| Stage I | 7 | 3 | 1 |
| Stage II | 4 | 0 | 2 |
| Stage III | 0 | 0 | 2 |
Data are presented as n
Patients investigated at disease onset are sub-divided depending on initial symptoms
Stage 0: normal chest radiograph
stage I: bilateral hilar adenopathy (BHL) without parenchymal shadowing
stage II: BHL with parenchymal shadowing
stage III: parenchymal shadowing without BHL