Tested on Gulf Medical Boards (DHA, SMLE, MOH & HAAD)
Clinical calculations and diagnostic scoring systems like Fisher Grade frequently appear on Prometric exams. Master high-yield clinical vignettes with instant AI-powered pathophysiology rationales.
What is the Fisher Grade?
The Fisher Grade is an evidence-based clinical decision rule engineered to quantify diagnostic probability, stratify clinical severity, and guide therapeutic decision-making in neurology practice. The Fisher Grade classifies the appearance of blood on a non-contrast CT scan of the head in patients with subarachnoid hemorrhage (SAH). It is used to predict the risk of delayed cerebral ischemia from vasospasm. Clinical scoring tools like Fisher Grade are essential in acute and outpatient management, enabling clinicians to objectively differentiate between low-risk candidates suitable for conservative therapy and high-risk patients requiring urgent interventions. Verified against current 2026 clinical standards, this tool is extensively tested on Gulf health authority licensing exams including DHA (Dubai), SMLE (Saudi Arabia), MOH, HAAD/DOH (Abu Dhabi), OMSB (Oman), and QCHP (Qatar).
💡Clinical Pearls & Diagnostic Utility
Aids in deciding the intensity of neurocritical care monitoring and the need for prophylactic measures (like nimodipine) against vasospasm, which typically peaks 4-14 days post-bleed.
Formula & Calculation Parameters
The mathematical equation and clinical variables required to calculate Fisher Grade:
Score Interpretation & Clinical Stratification
| Score Range | Clinical Interpretation | Risk Tier |
|---|---|---|
| ≤ 2 | Low Risk | green |
| 3 – 3 | Highest Risk | red |
| ≥ 4 | Moderate Risk | yellow |
When to Exercise Caution
The original scale has been criticized because Grade 3 has a higher risk of vasospasm than Grade 4. The Modified Fisher Scale (mFS) was later developed to correct this non-linear relationship.
Clinical Review Board
Dr. Muhammad Nouman, MBBS
Capital Medical University | PMDC Reg No: 117744-P
Clinical Audit Status
✓ Verified for 2026 Guidelines
Last updated: 2026-08-07
Peer-Reviewed Medical Literature
- •Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning. Neurosurgery. 1980;6(1):1-9.
Related Neurology Calculators & Scoring Tools
Explore related clinical calculators, risk stratification indexes, and diagnostic scoring algorithms in Neurology:
Glasgow Coma Scale (GCS)
Assesses the level of consciousness after neurological injury.
ABCD² Score for TIA
Estimates stroke risk after a transient ischemic attack (TIA).
Modified Rankin Scale (mRS)
Measures the degree of disability or dependence in daily activities after a stroke.
Pediatric Glasgow Coma Scale (pGCS)
Assesses level of consciousness in pre-verbal children and infants.
Hunt and Hess Scale
Predicts mortality in subarachnoid hemorrhage (SAH).
Intracerebral Hemorrhage (ICH) Score
Estimates 30-day mortality for spontaneous intracerebral hemorrhage.