Table 1 Reactivity grades for direct contact cytotoxicity [39]
Grade | Reactivity | Description of reactivity zone |
|---|---|---|
0 | None | No detectable zone around or under specimen |
1 | Slight | Zone limited to area under specimen |
2 | Mild | Zone extends less than 0.5Â cm beyond specimen |
3 | Moderate | Zone extends 0.5–1.0 cm beyond specimen |
4 | Severe | Zone extends greater than 1.0Â cm beyond specimen but does not involve entire dish |