Modified Rankin Scale (mRS) Calculator

inputs

Functional outcome grade

✓ when to use

Use to document functional outcome after stroke at discharge, 90 days, and in follow-up. mRS is the primary outcome measure in stroke trial design. Also used in clinical practice for communication about disability level and care planning.

✗ when not to use

mRS is a global disability scale, not a neurological deficit scale (use NIHSS for that). The mRS has moderate inter-rater reliability — structured interviews improve consistency. Not specific to stroke causes of disability; comorbidities can influence the grade.

clinical pearls

In stroke trials, 'good outcome' is typically defined as mRS 0–2 (independent), though some trials use mRS 0–1 for a more stringent threshold. Always check the definition used in the specific study.
A structured mRS interview improves inter-rater reliability significantly. Ask about specific activities (dressing, shopping, cooking, managing finances, walking) rather than relying on global impression.
Pre-stroke mRS is important context. A patient with pre-stroke mRS 3 (from prior stroke or comorbidity) achieving mRS 3 post-treatment has not worsened — this is different from a previously independent patient reaching mRS 3.
The ordinal shift analysis (comparing the full distribution of mRS scores between groups) is increasingly used in stroke trials instead of dichotomised outcomes, as it captures the full range of treatment effects.
mRS measures global disability — it does not capture specific neurological deficits, mood, cognitive function, or quality of life. Consider these outcomes alongside mRS in clinical practice.

✓ when to use

✗ when not to use

clinical pearls

In stroke trials, 'good outcome' is typically defined as mRS 0–2 (independent), though some trials use mRS 0–1 for a more stringent threshold. Always check the definition used in the specific study.
A structured mRS interview improves inter-rater reliability significantly. Ask about specific activities (dressing, shopping, cooking, managing finances, walking) rather than relying on global impression.
Pre-stroke mRS is important context. A patient with pre-stroke mRS 3 (from prior stroke or comorbidity) achieving mRS 3 post-treatment has not worsened — this is different from a previously independent patient reaching mRS 3.
The ordinal shift analysis (comparing the full distribution of mRS scores between groups) is increasingly used in stroke trials instead of dichotomised outcomes, as it captures the full range of treatment effects.
mRS measures global disability — it does not capture specific neurological deficits, mood, cognitive function, or quality of life. Consider these outcomes alongside mRS in clinical practice.

Modified Rankin Scale (mRS)

inputs

✓ when to use

✗ when not to use

clinical pearls

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