Understanding the Karnofsky scale

The Karnofsky Performance Status (KPS) scale, also known as the Karnofsky scale or Karnofsky index, is an assessment scale used by medical providers and caregivers to assess an individual’s functional status and their ability to perform activities of daily living.

Functional status is an individual’s ability to perform the daily activities required to meet one’s basic needs, achieve role responsibilities, and maintain overall health. 

Activities of daily living encompass routine tasks that most individuals can accomplish independently, including:

• Bathing and personal hygiene

• Toileting and continence management

• Dressing and grooming

• Feeding and nutrition

• Mobility and transfers

• Communication and cognitive tasks 

This article describes the history of the Karnofsky scale, how to assess KPS scores, adaptations of the scale, and more. 

Summary

• The Karnofsky scale is a widely-used 11-point assessment tool ranging from 0% to 100% that evaluates a patient's functional status and ability to perform activities of daily living, particularly valuable for prognosis in serious medical conditions.

• KPS scores help healthcare professionals determine care needs, with higher scores (80-100%) indicating independence, moderate scores (50-70%) showing need for assistance, and lower scores (0-40%) requiring institutional care.

• Understanding Karnofsky performance status is essential for mental health assessments, as functional decline often correlates with psychological well-being and can guide treatment planning across healthcare disciplines.

• The scale has evolved through modifications like the Thorne-modified and Australia-modified versions to better serve contemporary palliative and community care settings while maintaining its core assessment principles.

• Private practice healthcare professionals can utilize the Karnofsky scale to track patient progress, inform treatment decisions, coordinate care with other providers, and support documentation for insurance and disability determinations.

History of the Karnofsky scale

Developed in 1948, the Karnofsky scale remains one of the most valuable and widely-used assessment tools in healthcare for evaluating functional status and guiding clinical decision-making,

Oncologists David A. Karnofsky and Joseph H. Burchenal introduced the Karnofsky scale in their groundbreaking 1948 publication Evaluation of Chemotherapeutic Agents.

The scale's development traces back to an unexpected medical discovery during World War II. 

In 1943, the bombing of an American ship carrying nitrogen mustard in the Italian port of Bari led to a significant medical breakthrough. 

Army physicians observed that soldiers exposed to the chemical showed dramatically reduced white blood cell counts, leading researchers to investigate nitrogen mustard's potential therapeutic applications.

Subsequent research demonstrated that nitrogen mustard injections could induce remission in lymphoma patients, encouraging its experimental use as a last-resort treatment for lung cancer. 

Clinicians needed systematic methods to evaluate both objective improvements (such as reduced lung lesions and decreased metastases) and subjective improvements (including patient-reported strength, appetite, and symptom relief).

Most importantly for functional assessment, researchers needed to measure patients' performance status—their ability to carry out daily activities and their level of dependence on assistance. 

This comprehensive evaluation approach became the foundation for what we now know as the Karnofsky scale.

The KPS medical abbreviation (Karnofsky performance status) has since become standard terminology in healthcare settings worldwide, representing a universally understood measure of functional capacity that transcends specialty boundaries.

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Understanding the KPS score

The Karnofsky scale utilizes an 11-point rating system with percentages ranging from 100% (normal functioning) to 0% (death). 

When considering the Karnofsky score and prognosis, each percentage corresponds to specific functional capabilities and care requirements, providing healthcare professionals with clear guidelines for assessment and care planning.

At a KPS score of 100%, the individual has normal functioning, no complaints, and is without evidence of disease. A score of 90% denotes the individual can carry out normal activities with minor signs or symptoms of disease, and a score of 80% correlates with an individual who can complete normal activities with effort and has some signs or symptoms of disease. 

At 70%, the individual can care for themselves but is unable to carry on normal activities or do active work. 

A score of 60% denotes the individual requires occasional assistance but can care for most of their personal needs. When the individual is at 50%, they require considerable assistance and frequent medical care. 

At 40%, the individual is disabled and requires special care and support. With a score of 30%, an individual is severely disabled with hospital admission indicated, although death is not imminent. 

When the individual has a KPS score of 20%, they are very sick, with hospital admission and active supportive treatment necessary.

With a Karnofsky index score of 10%, the individual is moribund with fatal processes rapidly progressing. 

And, lastly, at 0%, the individual is dead. 

The lower the percentage, the worse the survival from illness. 

Within the scale are three performance statuses (conditions): 

• With a KPS score between 100% and 80%, an individual can perform normal activities and work, with no special care needed. 

• Between 70% and 50%, an individual is unable to work, but is able to live at home and care for most personal needs, with varying amounts of assistance needed. 

• Between 40% and 0%, individuals are unable to care for themselves and require the equivalent of institutional or hospital care with the disease progressing rapidly. 

The Karnofsky scale is used by trained examiners or clinicians. The person using the scale observes the client and obtains information regarding the client’s ability to perform daily activities, along with symptoms, limitations, and required support. 

At higher percentages, the KPS score reflects an individual’s ability to perform daily tasks and work. 

At lower percentages, the KPS score reflects needs for hospitalization and acute medical support. 

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Limitations and adaptations of the Karnofsky scale

While useful, the Karnofsky scale has limitations related to the structure of the healthcare system when it was created in 1948, particularly with regard to how the scale connects performance status with clinical care recommendations. 

The KPS index focuses on medical interventions which limits its use in non-hospital-based settings such as palliative care. For example, palliative care patients may be cared for at home or in hospice settings, while the Karnofsky scale  had recommended hospitalization for those patients with a score of 20% or lower. 

Due to the need for variability regarding recommendations in care settings, David Thorne developed a modified version of the Karnofsky scale in the 1990s, named Thorne-modified Karnofsky Performance Status scale (TKPS). 

Created specifically for use in community and palliative home care settings, the Thorne-modified Karnofsky Performance Status scale rephrased the categories on the lower ends of the Karnofsky scale to describe  professional care needs and activity while eliminating references to location of care. 

Due to this removal of location references, the Thorne-modified Karnofsky Performance Status Scale was then limited in its use for hospitalized palliative care patients. 

Due to this need, the Australia-modified Karnofsky Performance Status Scale (AKPS) was another assessment tool derived from the Karnofsky scale. 

The Australia-modified Karnofsky scale incorporates the Karnofsky Performance Status Scale and the Thorne-modified Karnofsky Performance Status Scale, accommodating evaluation in any setting of care. 

In the Australia-modified Karnofsky scale and the Thorne-modified Karnofsky Performance Status Scale, the link to health professionals' visits were eliminated, favoring a generic approach focusing on function alone.

Conclusion

The Karnofsky scale remains a fundamental and invaluable tool for healthcare professionals working across diverse practice settings and patient populations. 

For mental health therapists, nurse practitioners, speech-language pathologists, and occupational therapists in private practice, understanding and appropriately implementing the Karnofsky scale enhances clinical assessment, treatment planning, and interdisciplinary communication.

The evolution of the Karnofsky scale from its 1940s origins to contemporary applications demonstrates its enduring relevance and adaptability to changing healthcare needs. 

While recognizing its limitations, healthcare professionals can leverage KPS scores to provide more comprehensive, coordinated, and effective care for patients facing functional challenges.

As healthcare continues evolving toward more integrated, patient-centered approaches, the Karnofsky scale's role in facilitating communication among diverse healthcare professionals becomes increasingly important. 

By incorporating this standardized assessment into routine practice, healthcare professionals can better serve their patients while contributing to the broader goals of improved quality of life and optimal functional outcomes.

Ultimately, the Karnofsky scale serves not just as an assessment tool, but as a bridge connecting objective functional evaluation with compassionate, individualized patient care. 

For private practice clinicians, mastering its application represents an investment in providing the highest quality care while supporting patients and families through some of life's most challenging transitions.

Sources

• Crooks, V., Waller, S., Smith. T., & Hahn, Theodore. (1991). The use of the Karnofsky performance scale in determining outcomes and risk in geriatric outpatients. Journal of Gerontology. 

• Coscarelli Schag, C., Heinrich, R. L., & Ganz, P. A. (1984). Karnofsky performance status revisited: Reliability, validity, and guidelines. Journal of Clinical Oncology. 

• Abernethy, A. P., Shelby-James, T., Fazekas, B. S., Woods, D., & Curroq, D. C. (2005). The Australia-modified Karnofsky performance status (AKPS) scale: A revised scale for contemporary palliative care clinical practice [ISRCTN81117481]. BMC Palliative Care. 

• American Thoracic Society. (2007). Functional status. 

• EBSCO Information Service. (2025). Karnofsky performance status (KPS). 

• Physiopedia. (2025). Karnofsky performance status scale. 

• Peus, D., Newcomb, N. & Hofer, S. (2013). Appraisal of the Karnofsky Performance Status and proposal of a simple algorithmic system for its evaluation. BMC Medical Informatics and Decision Making. 

• Edemekong, P. F., Bomgaars, D. L., Sukumaran. S., & Schoo, C.(2025, May 4). Activities of Daily Living. In StatPearls. StatPearls Publishing. Retrieved September 10, 2025.

• Daoud, A. M. O, Mohamed Khalaf, M., & Nassar, M. (2022). Limitations of the Karnofsky Performance Status Scale in kidney transplant recipients. Annals of Medicine. 

• Timmermann, C. (2012). ‘Just give me the best quality of life questionnaire’: The Karnofsky scale and the history of quality of life measurements in cancer trials. Chronic Illness. 

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