What NIHSS score qualifies for tPA (thrombolytic therapy)?

There is no strict NIHSS cutoff for tPA eligibility, but it is generally considered for scores ≥ 4 within the treatment window (up to 4.5 hours from symptom onset). Very mild strokes (NIHSS 0–4) may not benefit from tPA, and very severe strokes (NIHSS > 25) have higher bleeding risk.

How long does it take to perform the NIHSS?

A trained examiner can complete the NIHSS in approximately 5–8 minutes. All healthcare providers performing stroke assessments should be NIHSS-certified through standardized training programs.

Can the NIHSS miss posterior circulation strokes?

Yes. The NIHSS is weighted toward anterior circulation deficits (language, motor). Posterior circulation strokes causing vertigo, ataxia, visual field cuts, or cranial nerve palsies may receive low NIHSS scores despite significant clinical severity.

For licensed healthcare professionals only. Not a diagnostic tool. See full disclaimer.

NIH Stroke Scale (NIHSS)

Neurological Assessment

1a. Level of Consciousness

1b. LOC Questions (month, age)

1c. LOC Commands (open/close eyes, grip/release)

2. Best Gaze

3. Visual Fields

4. Facial Palsy

5a. Motor Arm — Left

5b. Motor Arm — Right

6a. Motor Leg — Left

6b. Motor Leg — Right

7. Limb Ataxia

8. Sensory

9. Best Language

10. Dysarthria

11. Extinction / Inattention

NIHSS Score

No stroke symptoms

About

The National Institutes of Health Stroke Scale (NIHSS) is a systematic assessment tool that provides a quantitative measure of stroke-related neurological deficit. It is used to evaluate the severity of acute stroke, guide treatment decisions (including thrombolytic therapy eligibility), and predict patient outcomes. The NIHSS evaluates 11 items across 15 assessments, with scores ranging from 0 (no deficit) to 42 (maximum deficit).

Formula

NIHSS = Sum of all 15 item scores

Range: 0 (no stroke symptoms) to 42 (maximum deficit)

Interpretation

NIHSS Score	Stroke Severity
0	No stroke symptoms
1 – 4	Minor stroke
5 – 15	Moderate stroke
16 – 20	Moderate to severe stroke
21 – 42	Severe stroke

References

FAQ

Related Calculators

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ABCD²

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GCS

Assess level of consciousness using the Glasgow Coma Scale.

Disclaimer

For educational and informational purposes only. Not intended to replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional.