The Karnofsky Performance Status (KPS) is a scoring system that rates a person’s ability to perform everyday activities on a scale from 0 to 100, in increments of 10. A score of 100 means fully functional with no symptoms, while 0 means death. Oncologists use it to track how well a patient is functioning overall, guide treatment decisions, and determine eligibility for clinical trials. Developed in the late 1940s by David Karnofsky and Joseph Burchenal during early cancer chemotherapy trials, it remains one of the most widely used tools in cancer care today.
Why the Scale Was Created
The KPS grew out of some of the earliest experiments with chemotherapy drugs. Karnofsky and Burchenal were testing nitrogen mustard on lung cancer patients and needed a way to capture something that tumor measurements alone couldn’t: how the patient was actually doing day to day. A tumor might shrink on a scan, but if the patient was still bedridden, that response told an incomplete story.
As Karnofsky and Burchenal explained at the time, “subjective and objective evidence of improvement can occur in a patient, while the patient remains bedridden.” They wanted a single number that described a patient’s ability to carry on normal activities, their need for help with daily care, or their dependence on constant medical support. That number became the performance status score, expressed as a percentage from 0 to 100.
The Full 0 to 100 Scale
Each 10-point increment on the KPS corresponds to a specific level of functioning. The scale breaks into three broad tiers: people who can function normally (80 to 100), people who can live at home but need varying amounts of help (50 to 70), and people who cannot care for themselves (0 to 40).
- 100: Normal function, no complaints, no evidence of disease.
- 90: Able to carry on normal activity with minor signs or symptoms.
- 80: Normal activity with effort; some signs or symptoms present.
- 70: Cares for self but unable to carry on normal activity or do active work.
- 60: Requires occasional assistance but can handle most personal needs.
- 50: Requires considerable assistance and frequent medical care.
- 40: Disabled; requires special care and assistance.
- 30: Severely disabled; hospitalization indicated, though death is not imminent.
- 20: Very sick; hospitalization and active supportive care necessary.
- 10: Actively dying; fatal processes progressing rapidly.
- 0: Dead.
The distinction between, say, 60 and 70 can feel subtle on paper, but the key dividing line is whether someone needs help from another person. At 70 and above, you’re managing your own care. At 60 and below, you’re relying on others to some degree.
How KPS Scores Guide Treatment
KPS scores directly influence which treatments are offered and whether a patient qualifies for a clinical trial. In oncology, chemotherapy eligibility is often tied to a KPS of 80 or higher, which corresponds to someone who can still perform normal activities even if it takes extra effort. Some trials set the threshold at 60 or above, opening enrollment to patients who need occasional help but are still largely independent.
The score also serves as an independent predictor of survival. In a large study of over 17,000 liver cancer patients awaiting transplant, five-year overall survival was 77.6% for those with high KPS scores (80 to 100), 73.7% for moderate scores (50 to 70), and 66.3% for low scores (10 to 40). Patients with the lowest scores also had a higher rate of cancer recurrence: 7.4% at five years, compared to about 5% in the higher-functioning groups. Even after accounting for other factors like tumor size and staging, KPS remained an independent predictor of outcomes. The pattern holds across many cancer types: lower functional status at the time of treatment consistently correlates with shorter survival.
This is why your care team reassesses your KPS periodically. A declining score can signal that the disease is progressing or that treatment side effects are taking a toll, prompting a shift in the care plan toward less aggressive therapy or a greater focus on comfort.
Who Performs the Assessment
A doctor, nurse, or other clinician assigns the score based on observation and conversation. There’s no blood test or scan involved. The clinician watches how you move, asks about your daily routine, and determines which description on the scale best fits your current state.
Because the assessment is subjective, different clinicians can arrive at slightly different scores for the same patient. Studies measuring agreement between raters have found reasonably strong consistency. In one study, correlation between two physicians scoring the same patients was 0.82, while agreement between a physician and a nurse ranged from 0.76 to 0.77. That’s good but not perfect, which is why some institutions have standardized training for the assessment.
KPS Compared to the ECOG Scale
The other widely used performance scale in oncology is the ECOG (Eastern Cooperative Oncology Group) scale, which uses a simpler 0 to 5 range instead of 0 to 100. Both measure the same thing, functional ability, but ECOG collapses the detail into fewer categories. Many clinical trials and treatment guidelines reference both, and there’s a commonly used conversion between them:
- ECOG 0 (fully active) maps to KPS 90 to 100.
- ECOG 1 (restricted in strenuous activity, but ambulatory) maps to KPS 70 to 80.
- ECOG 2 (up and about more than half the day, but unable to work) maps to KPS 50 to 60.
- ECOG 3 (in bed or a chair more than half the day, limited self-care) maps to KPS 30 to 40.
- ECOG 4 (completely disabled, no self-care) maps to KPS 10 to 20.
- ECOG 5 maps to KPS 0 (dead).
ECOG is more common in clinical trial protocols because of its simplicity, while KPS offers more granularity. If your oncologist mentions one and a trial uses the other, the conversion above is what they’ll use to translate.
KPS in Palliative and End-of-Life Care
In palliative care settings, a modified version called the Palliative Performance Scale (PPS) is often used instead. The PPS adds columns for oral intake and level of consciousness, which become increasingly relevant as patients approach end of life. Despite the added dimensions, studies have found a direct linear relationship between KPS and PPS scores, and the two can be used interchangeably within prognostic tools designed to estimate survival in palliative patients.
For patients and families, the practical takeaway is that a declining KPS or PPS score is one of several signals that the focus of care may shift from trying to cure or control the disease to maximizing comfort and quality of life. A score below 50 generally indicates someone who needs substantial daily assistance, and scores of 30 or below typically reflect a person who is no longer able to care for themselves at all.