Table 3   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