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Printed on 4/21/2026
For informational purposes only. This is not medical advice.
The Frailty Index (FI) based on 40 deficits quantifies frailty as the proportion of accumulated health deficits. It follows the deficit-accumulation model, where FI = deficits present divided by total deficits considered. Higher values reflect greater biologic vulnerability and are associated with higher risks of hospitalization, disability, institutionalization, and mortality.
Formula: FI-40 = deficits present / 40 (range 0-1).
Frailty Index interpretation is continuous; category bands are practical risk-communication groupings rather than universally fixed diagnostic thresholds.
Higher FI-40 values indicate higher cumulative frailty burden and support more proactive risk-informed care planning.
Use in geriatric assessment, longitudinal monitoring, and research or quality pathways where a deficit-accumulation frailty model is desired.
Results depend on deficit selection and data completeness; FI should be interpreted alongside functional and clinical context, not in isolation.
For related assessments, see Electronic Frailty Index, Clinical Frailty Scale and FRAIL Scale.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
Classify eFI values into fit, mild, moderate, or severe frailty categories using common thresholds.
GeriatricsAssess frailty using the Rockwood Clinical Frailty Scale (CFS 1–9): Very Fit to Terminally Ill. Used for ICU triage, surgical risk stratification, and goals-of-care discussions in elderly patients.
GeriatricsScreen frailty using the 5-item FRAIL scale (Fatigue, Resistance, Ambulation, Illnesses, Loss of weight).
GeriatricsClassify hospital frailty risk category from HFRS value (<5 low, 5-15 intermediate, >15 high).