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Fisher Scale

Fisher Scale: calculated with the published clinical method, with result interpretation. A reference tool that does not replace a doctor's advice.

ℹ Reference calculation based on the published method. It does not replace a clinical examination or a doctor's decision.

Fisher Scale

Subarachnoid blood on CT (1 = yes)
Localised clot or vertical layer ≥1 mm (1 = yes)
Clot completely filling ≥1 cistern or fissure (1 = yes)
Intraventricular haemorrhage (1 = yes)
Intracerebral haematoma (1 = yes)
Fisher scale (group)
3
Graded on the initial CT in aneurysmal SAHClassification from the CT report; layer thickness is judged by the radiologistFisher Scale: calculated with the published clinical method, with result interpretation. A reference tool that does not replace a doctor's advice.
Vasospasm risk (Fisher)
Highest (group 3)
Modified Fisher scale
3
Vasospasm OR (vs grade 0–1)
1.6

More about: Fisher Scale

What it calculates

The “Fisher Scale” calculator computes Fisher scale (group) from 5 parameters: subarachnoid blood on ct (1 = yes), localised clot or vertical layer ≥1 mm (1 = yes), clot completely filling ≥1 cistern or fissure (1 = yes), intraventricular haemorrhage (1 = yes), intracerebral haematoma (1 = yes).

Used by professionals and patients to assess health metrics, dosages, and risks.

Example calculation

With parameters Subarachnoid blood on CT (1 = yes) = 1, Localised clot or vertical layer ≥1 mm (1 = yes) = 1, Clot completely filling ≥1 cistern or fissure (1 = yes) = 1, Intraventricular haemorrhage (1 = yes) = 0, Intracerebral haematoma (1 = yes) = 0 the result is 3 (Graded on the initial CT in aneurysmal SAH).

How to use

  1. Enter subarachnoid blood on ct (1 = yes), localised clot or vertical layer ≥1 mm (1 = yes), clot completely filling ≥1 cistern or fissure (1 = yes), intraventricular haemorrhage (1 = yes) and intracerebral haematoma (1 = yes) — each field above is adjustable with a slider.
  2. Fisher scale (group) is calculated automatically as you type.
  3. Check the worked example below to see the formula applied to real numbers.
  4. Copy the result or bookmark this calculator.

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FAQ

How is BMI calculated?
BMI = weight (kg) / height (m)². Example: 70 kg / (1.75 m)² = 22.9. The WHO normal range is 18.5–24.9; below that is underweight, 25–29.9 is overweight, and 30+ is obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so athletes may show a high BMI with low body fat. It is also less reliable for teenagers, pregnant people, older adults, and very tall or short individuals.
What are the BMI categories?
Underweight: below 18.5. Normal: 18.5–24.9. Overweight: 25–29.9. Obese class I: 30–34.9; class II: 35–39.9; class III: 40+.
What is a better measure than BMI?
Body fat percentage, waist-to-height ratio (aim for under 0.5), and waist circumference give a clearer picture of health than BMI alone.

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