Heaf testing
| Heaf test grade | Reaction |
| Negative | No induration |
| 1 | 4–6 papules |
| 2 | Confluent papules form indurated ring |
| 3 | Central filling to form disc |
| 4 | Disc >10 mm with or without blistering |
The equivalent Mantoux positive levels done with 10 TU (0.1 ml 100 TU/ml, 1:1000) are 5–14 mm induration (Heaf 2) and >15 mm induration (Heaf 3–4), respectively.12