Karnofsky Performance Scale Calculator

The Karnofsky Performance Status rates functional capacity from 0 to 100 in steps of 10, and its structure is three bands rather than eleven independent points. Scores of 80 to 100 describe a person able to carry on normal activity and work, with 100 meaning no complaints and no evidence of disease and 80 meaning normal activity that requires effort. Scores of 50 to 70 describe someone unable to work but living at home with increasing assistance, 70 marking preserved self-care and 50 requiring considerable help and frequent medical care. Scores of 0 to 40 describe inability to self-care and a need for institutional or equivalent care, with 30 indicating severe disability warranting hospitalization and 10 a moribund state. That finer granularity is why the scale persists alongside the simpler ECOG grades, particularly in neuro-oncology, radiation oncology, and palliative care where a shift from 80 to 70 changes management. A threshold of 70 recurs throughout: it separates recursive partitioning analysis classes in malignant glioma, appears in the Graded Prognostic Assessment for brain metastases, and commonly triggers palliative care consultation, while 50 or below supports hospice discussion. Reported median survival near KPS 50 in advanced cancer is on the order of 8 to 12 weeks. Recognized weaknesses include inter-observer variability in the 50 to 70 range, no adjustment for age-related baseline function, and poor capture of cognition and mood.

David A. Karnofsky and Joseph H. Burchenal devised the scale at Memorial Hospital in New York in the late 1940s while evaluating nitrogen mustard, one of the first cytotoxic drugs, in bronchogenic carcinoma. The problem they faced was that tumor shrinkage alone said nothing about whether a toxic drug had actually helped the patient, so they proposed grading subjective improvement and performance alongside objective response. The scale was set out in their 1949 chapter, The Clinical Evaluation of Chemotherapeutic Agents in Cancer, in the volume Evaluation of Chemotherapeutic Agents edited by Colin MacLeod. Formal validation came much later. Vincent Mor and colleagues published a reliability and validity assessment in Cancer in 1984, and John Yates and coworkers reported its application in patients with advanced cancer in the same period, establishing the score as a prognostic variable rather than merely a descriptive one. Derivative instruments followed: the Palliative Performance Scale, developed at Victoria Hospice in British Columbia in 1996, keeps the 0 to 100 framework but adds explicit ratings of ambulation, oral intake, and level of consciousness. The scale's longevity owes less to measurement precision than to the fact that some seventy years of oncology outcome data are recorded in its units.