| Grade | Definition | Karnofsky score |
| 0 | Fully active, able to carry on all pre-disease performance without restriction |
90-100 |
| 1 | Restricted in physically strenuous activity, but ambulatory and able to carry out work of a light or sedentary nature, i.e., light house work, office work |
70-80 |
| 2 | Ambulatory and capable of all self care, but unable to carry out any work activities. Up and about more than 50% of waking hours |
50-60 |
| 3 | Capable of only limited self care, confined to bed or chair more than 50% of waking hours |
30-40 |
| 4 | Completely disabled. Can not carry on any self care. Totally confined to bed or chair |
10-20 |