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APACHE II (APACHE II score)

APACHE II: 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.

APACHE II

Temperature (rectal)°C
Mean arterial pressuremmHg
Heart ratebpm
Respiratory rate/min
FiO₂%
PaO₂mmHg
PaCO₂mmHg
Arterial pH
Sodiummmol/L
Potassiummmol/L
Creatinineµmol/L
Acute kidney injury (1 = yes)
Hematocrit%
White blood cells×10⁹/L
Glasgow Coma Scalepoints
Ageyears
Severe organ insufficiency / immunocompromise (0 no, 1 elective surgery, 2 emergency surgery or non-operative)
APACHE II score
3
Worst values in the first 24 h in ICUMortality is approximate (Knaus, 1985)APACHE II: calculated with the published clinical method, with result interpretation. A reference tool that does not replace a doctor's advice.
Acute Physiology Score (APS)
0
Non-operative mortality
4%
Postoperative mortality
1%

More about: APACHE II (APACHE II score)

What it calculates

The “APACHE II (APACHE II score)” calculator computes APACHE II score from 17 parameters: temperature (rectal) (°C), mean arterial pressure (mmHg), heart rate (bpm), respiratory rate (/min), fio₂ (%), pao₂ (mmHg), paco₂ (mmHg), arterial blood ph, sodium (mmol/L), potassium (mmol/L), creatinine (µmol/L), acute kidney injury (1 = yes), hematocrit (%), white blood cells (×10⁹/L), glasgow coma scale (points), age (years), severe organ insufficiency / immunocompromise (0 no, 1 elective surgery, 2 emergency surgery or non-operative).

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

Example calculation

With parameters Temperature (rectal) = 37 °C, Mean arterial pressure = 85 mmHg, Heart rate = 90 bpm, Respiratory rate = 18 /min, FiO₂ = 21 %, PaO₂ = 90 mmHg, PaCO₂ = 40 mmHg, Arterial blood pH = 7.4, Sodium = 140 mmol/L, Potassium = 4 mmol/L, Creatinine = 90 µmol/L, Acute kidney injury (1 = yes) = 0, Hematocrit = 40 %, White blood cells = 10 ×10⁹/L, Glasgow Coma Scale = 15 points, Age = 60 years, Severe organ insufficiency / immunocompromise (0 no, 1 elective surgery, 2 emergency surgery or non-operative) = 0 the result is 3 (Worst values in the first 24 h in ICU).

How to use

  1. Enter temperature (rectal), mean arterial pressure, heart rate, respiratory rate, fio₂, pao₂, paco₂, arterial blood ph, sodium, potassium, creatinine, acute kidney injury (1 = yes), hematocrit, white blood cells, glasgow coma scale, age and severe organ insufficiency / immunocompromise (0 no, 1 elective surgery, 2 emergency surgery or non-operative) — each field above is adjustable with a slider.
  2. APACHE II score 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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