Contents · 13 sections
- 1. Glasgow Coma Scale (GCS)
- 2. CURB-65 — Severity of Community-Acquired Pneumonia
- 3. CHA₂DS₂-VASc — Stroke Risk in Atrial Fibrillation
- 4. HAS-BLED — Bleeding Risk on Anticoagulants
- 5. qSOFA — Sepsis Screening
- 6. Wells' Score — PE Probability
- 7. SOFA — Organ Dysfunction Assessment
- 8. Apgar Score — Newborn Assessment
- 9. Child-Pugh — Severity of Liver Cirrhosis
- 10. Charlson Comorbidity Index (CCI)
- How to memorize clinical scales
- Full list of scales on the platform
- Summary
Clinical scales are standardized tools for the objective assessment of a patient's condition. They translate a physician's subjective observations into a numerical score, which guides clinical decisions: whether to hospitalize or treat outpatient, prescribe anticoagulants or not, and transfer to the ICU or keep in the ward.
In this article, we cover 10 scales that every physician and senior medical student must know. For each scale, we detail when to use it, how to calculate it, and where to find the interactive calculator.
1. Glasgow Coma Scale (GCS)
Purpose: assessment of the level of consciousness in any emergency setting — TBI, stroke, intoxication, metabolic disorders.
How to calculate: three components — eye opening (1–4), verbal response (1–5), motor response (1–6). Total score ranges from 3 to 15.
- 13-15 — mild impaired consciousness
- 9-12 — moderate
- 3-8 — severe (indication for intubation)
Important: GCS ≤ 8 — "intubate" — is one of the most well-known rules in emergency medicine.
2. CURB-65 — Severity of Community-Acquired Pneumonia
Purpose: to determine where to treat pneumonia — outpatient, inpatient, or in the ICU.
Criteria (1 point each):
- Confusion — altered mental status
- Urea > 7 mmol/L
- Respiratory rate ≥ 30/min
- Blood pressure — systolic < 90 or diastolic ≤ 60 mmHg
- 65 — age ≥ 65 years
Management: 0–1 — outpatient, 2 — inpatient, 3–5 — consider ICU admission.
3. CHA₂DS₂-VASc — Stroke Risk in Atrial Fibrillation
Purpose: to decide whether anticoagulants are needed for a patient with atrial fibrillation.
Criteria:
- CHF — heart failure (1 point)
- Hypertension — hypertension (1)
- Age ≥ 75 years (2 points)
- Diabetes — diabetes (1)
- Stroke/TIA — history of stroke/TIA (2 points)
- Vascular disease — vascular disease (1)
- Age 65-74 (1)
- Sex — female sex (1)
Management: ≥ 2 points in men (≥ 3 in women) — oral anticoagulants are indicated.
4. HAS-BLED — Bleeding Risk on Anticoagulants
Purpose: to assess bleeding risk in a patient on anticoagulant therapy. Used in conjunction with CHA₂DS₂-VASc.
Criteria (1 point each): hypertension, abnormal renal/liver function, stroke, bleeding history, labile INR, age > 65, NSAID/alcohol use.
Management: ≥ 3 — high bleeding risk, but this is not a contraindication to anticoagulants, rather a reason for closer monitoring.
5. qSOFA — Sepsis Screening
Purpose: to quickly identify patients with suspected sepsis at the bedside without laboratory tests.
Criteria (1 point each):
- Systolic BP ≤ 100 mmHg
- Respiratory rate ≥ 22/min
- Altered mental status (GCS < 15)
Management: ≥ 2 points — high risk of sepsis, urgent workup (lactate, blood cultures) and initiation of therapy are required.
6. Wells' Score — PE Probability
Purpose: to assess the clinical probability of pulmonary embolism and determine further diagnostic management.
Key criteria: tachycardia >100, immobilization/surgery, history of PE/DVT, hemoptysis, malignancy, clinical signs of DVT, alternative diagnosis less likely.
Management: low probability — D-dimer, high probability — immediate CT pulmonary angiography.
7. SOFA — Organ Dysfunction Assessment
Purpose: objective assessment of multi-organ failure severity in the ICU. A diagnostic criterion for sepsis according to Sepsis-3.
How to calculate: 6 organ systems (respiration, coagulation, liver, cardiovascular, CNS, renal), each scored from 0 to 4. Maximum is 24.
Management: an increase in SOFA ≥ 2 from baseline + suspected infection = sepsis (Sepsis-3).
8. Apgar Score — Newborn Assessment
Purpose: rapid assessment of the newborn's condition at the 1st and 5th minutes of life.
Criteria (0-2 points each): heart rate, respiration, muscle tone, reflexes, skin color.
- 7-10 — normal
- 4-6 — moderate asphyxia
- 0-3 — severe asphyxia, resuscitation required
9. Child-Pugh — Severity of Liver Cirrhosis
Purpose: classification of cirrhosis severity and survival prediction. Determines treatment management and indications for transplantation.
Criteria: bilirubin, albumin, INR, ascites, encephalopathy.
- Class A (5-6 points) — compensated cirrhosis
- Class B (7-9) — subcompensated
- Class C (10-15) — decompensated, consider transplantation
10. Charlson Comorbidity Index (CCI)
Purpose: prediction of 10-year survival taking into account comorbidities. Used in oncology, surgery, and when deciding on treatment aggressiveness.
How to calculate: each comorbid condition is assigned a weight (from 1 to 6). Myocardial infarction, heart failure, COPD, peptic ulcer disease — 1 point. Hemiplegia, CKD, diabetes with complications — 2. Severe liver disease — 3. Metastatic tumor, AIDS — 6.
→ Charlson Comorbidity Index calculator
How to memorize clinical scales
Cramming all criteria by heart is inefficient. Here is what works:
- Use them in practice. Every time you see a patient with pneumonia, calculate CURB-65. With atrial fibrillation — CHA₂DS₂-VASc. After 10 patients, you will remember the scale naturally.
- Decode abbreviations. CHA₂DS₂-VASc — each letter = a criterion. Know the abbreviation — know the scale.
- Practice with calculators. Interactive calculators on the platform allow you to run through the scale in 30 seconds and see the interpretation.
- Tie them to clinical scenarios. Not "qSOFA is BP, RR, consciousness", but "call to the emergency department, fever + low blood pressure → calculating qSOFA".
Full list of scales on the platform
In addition to the ten described, another 40 clinical calculators are available on the WhiteCoat Pro platform:
- Pulmonology: PESI, sPESI, Geneva score
- Neurology: modified Rankin Scale, 4AT, ABCD²
- Cardiology: HEART Score, NYHA, Killip
- Hepatology: MELD, Maddrey, FIB-4, APRI
- Nephrology: GFR (CKD-EPI), Padua
- Surgery/Oncology: Alvarado, ASA, Charlson, ECOG, Karnofsky
- Screening: AUDIT-C, AUDIT (full), CAGE, BMI
All 50 clinical scales and calculators →
Conclusion
Clinical scales are not abstract textbook theory. They are working tools that doctors use every day. Learn these ten, and you will feel more confident making decisions on-call, at exams, and in residency.