Criteria and decolorization for zone and lysis index
| Index | Decolorization of zone and lysis index |
|---|---|
| Zone | |
| 0 | No detectable decolorization zone around or under specimen |
| 1 | Decolorization zone limited to area under specimen |
| 2 | Decolorization zone extends less than 0.5 cm beyond specimen |
| 3 | Decolorization zone extends 0.5 cm to 1.0 cm beyond specimen |
| 4 | Decolorization zone extends further than 1.0 cm beyond specimen but dose not involve entire dish |
| 5 | Decolorization zone involves entire dish |
| Lysis | |
| 0 | No observable cytotoxicity |
| 1 | < 20% of the decolorized zone affected |
| 2 | 20% to 40% of the decolorized zone affected |
| 3 | 40% to 60% of the decolorized zone affected |
| 4 | 60% to 80% of the decolorized zone affected |
| 5 | > 80% of the decolorized zone affected |
