Neurology
Modified Rankin Scale (mRS)
Degree of disability after stroke.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The Modified Rankin Scale (mRS) is a single ordered measure of global disability and dependence, used most commonly after stroke. It runs from 0 (no symptoms) through increasing levels of disability to 6 (death). The intermediate grades describe the spectrum from no significant disability (1) and slight disability with independence (2), through moderate disability needing some help (3) and moderately severe disability needing help with walking and daily activities (4), to severe disability requiring constant care (5). It is the standard functional outcome measure in stroke care and clinical trials.
Interpreting the result
Scores of 0–2 are generally regarded as functional independence, 3–5 as dependence of increasing severity, and 6 as death. The threshold between 2 and 3 is clinically important, as it marks the line between living independently and needing assistance, and is often used as a trial outcome (a "good" outcome being 0–2). Because it is a single global judgement, the grade should reflect the patient's overall functional state rather than any one symptom. Structured interview tools improve consistency of grading.
Worked example
A patient three months after a stroke can walk and look after herself but can no longer manage all her previous activities and needs occasional help — this corresponds to mRS 3 (moderate disability, needs some help, walks unaided), placing her in the dependent range.
Pearls / pitfalls
- The 0–2 versus 3–5 split (independent versus dependent) is the most clinically meaningful threshold and a common trial endpoint.
- Grading is subjective, so inter-rater variability can be substantial; structured interviews improve consistency.
- It captures global disability, not stroke severity at onset, and is best assessed at a defined time point such as 90 days.
- Pre-existing disability should be recorded, as a baseline mRS affects interpretation of any change.
Evidence & validation
The scale evolved from the original Rankin scale, with the modified version and assessments of its reliability described by van Swieten and colleagues (Stroke, 1988); it is the recommended primary disability outcome in stroke trials and is used widely in routine practice.
Frequently asked questions
What mRS score counts as a good outcome?
A score of 0–2 represents functional independence and is widely used as the threshold for a "good" outcome in stroke trials. Scores of 3–5 indicate increasing dependence, and 6 means death.
When should the mRS be measured?
It is usually assessed at a defined time point, most often 90 days after stroke, so that outcomes are comparable. Earlier scores reflect the acute phase rather than the eventual functional state.
Why is the mRS sometimes inconsistent between assessors?
Because it is a single global judgement, different assessors can grade the same patient slightly differently. Using a structured interview improves reliability and is recommended where outcomes matter, such as trials.
Does the mRS measure stroke severity?
No. It measures global disability and dependence, which is an outcome, rather than the severity of the stroke at onset; tools such as the NIHSS are used to grade acute severity.
How is pre-existing disability handled?
A baseline mRS should be recorded before the event, because someone may already have disability. Interpreting an outcome score requires knowing the starting point so that any change can be judged.
References
- van Swieten JC, Koudstaal PJ, Visser MC, et al. Interobserver agreement for the assessment of handicap in stroke patients. Stroke. 1988;19(5):604–607.
- Royal College of Physicians. National Clinical Guideline for Stroke for the UK and Ireland.
Related calculators
Need a calculator we don't have — or a custom tool?
We build evidence-led clinical calculators, dashboards and reference tools for teams.