10 Emergency Department Scores Every Junior Doctor Should Know

Clinical scores are everywhere in emergency medicine. They structure your assessment, make decisions traceable and speed up handover. They are also routinely misused: treated as diagnoses rather than probabilities, applied outside the population they were built in, or used instead of clinical judgement.

Below are ten scores that students and junior doctors should know well, with the criteria, the key numbers from the original papers, and how current guidelines position them.

All calculators in one place: Medical calculators.

1. CRB-65: can this pneumonia be managed at home?

CRB-65 needs no blood tests, which makes it usable in primary care and at triage. One point each for [1]:

In the German CAPNETZ cohort, mortality was 0% with a score of 0, 6% with 1–2 and 23% with 3–4 [1].

The German S3 guideline on community-acquired pneumonia (2021) is clear that clinical judgement comes first. CRB-65 should be supplemented by [1]:

• functional status (for example, being chronically bedbound),
• assessment of potentially unstable comorbidities,
• oxygenation (pulse oximetry; blood gas in the emergency department).

In older patients and nursing home residents, a low CRB-65 alone does not reliably predict low risk [1].

2. CURB-65: adding urea

CURB-65 adds urea >7 mmol/L and was derived by Lim and colleagues in 2003 from UK, New Zealand and Dutch cohorts [2]. Thirty-day mortality rose with the score: 0 points 0.7%, 1 point 3.2%, 2 points 3%, 3 points 17%, 4 points 41.5%, 5 points 57% [2].

CRB-65 vs CURB-65: they perform similarly. The German guideline prefers CRB-65 because it needs no lab test and predicts mortality comparably to more complex scores such as CURB-65 and PSI [1]. CURB-65 is widely used in UK hospitals and appears often in English-language literature, so you need to know both.

Calculator: CURB-65.

3. Wells score for suspected pulmonary embolism

The Wells score estimates pretest probability of pulmonary embolism (PE). Items from the 2000 derivation study [3]:

Two ways to read it [3]:

• three-tier: low <2, moderate 2–6, high >6
• two-tier: PE unlikely ≤4, PE likely >4

In the original study, PE occurred in 2.2% (derivation) and 1.7% (validation) of patients with a score ≤4 and a negative D-dimer [3].

How the 2019 ESC guideline uses it [4, 5]: with low or intermediate clinical probability, D-dimer is the first test, and a negative result means no treatment is needed. With high probability, go straight to CT pulmonary angiography. An age-adjusted D-dimer cut-off (age × 10 µg/L above 50) should be considered (class IIa).

Calculator: Wells score for PE.

4. PERC: when not to test at all

The Pulmonary Embolism Rule-out Criteria are intended for emergency department patients whose pretest probability is already so low that testing should not be started. The rule is negative only if all eight items are met [5]:

• age <50
• heart rate <100/min
• SpO₂ >94%
• no unilateral leg swelling
• no haemoptysis
• no recent trauma or surgery
• no prior venous thromboembolism
• no oral hormone use

Apply PERC only after you have judged clinical probability to be low.

5. HEART score for chest pain

The HEART score was developed in the Netherlands and gives 0–2 points each for History, ECG, Age, Risk factors and Troponin, for a total of 0–10.

In the prospective validation (2,440 patients, ten Dutch hospitals) [6]:

Discrimination was better than TIMI and GRACE (c-statistic 0.83 vs 0.75 and 0.70) [6].

Context: for suspected NSTE-ACS, the ESC acute coronary syndrome guideline is built around high-sensitivity troponin algorithms (0 h/1 h or 0 h/2 h) [7]. HEART does not replace them. It helps structure overall risk and supports discharge decisions in low-risk patients.

Calculator: HEART score.

6. qSOFA: a prognostic flag, not a screening test

qSOFA came with the Sepsis-3 definitions in 2016 [8]. One point each for:

• respiratory rate ≥22/min
• altered mentation
• systolic blood pressure ≤100 mmHg

A score of 2 or more identifies patients with suspected infection who are more likely to have poor outcomes [8].

The classic error is using qSOFA as a screening tool. The Surviving Sepsis Campaign 2021 recommends against using qSOFA, compared with SIRS, NEWS or MEWS, as a single screening tool for sepsis, because of its poor sensitivity [9]. A negative qSOFA does not rule out sepsis. More in Sepsis screening: qSOFA, SOFA and NEWS2 compared.

Calculator: qSOFA.

7. NEWS2: catching deterioration early

The Royal College of Physicians' National Early Warning Score 2 (2017) aggregates six physiological parameters: respiratory rate, oxygen saturation, systolic blood pressure, pulse, level of consciousness or new confusion, and temperature. Supplemental oxygen adds 2 points [10].

Trigger thresholds [11]:

• ≥5: urgent clinical review
• ≥7: emergency response, e.g. by a team with critical care competencies
• 3 in any single parameter: clinician review even if the total is low

A separate SpO₂ scale (target 88–92%) exists for patients with confirmed hypercapnic respiratory failure; a competent clinician decides when to use it [11].

8. Glasgow Coma Scale

Teasdale and Jennett introduced the GCS in 1974 [12]. Three components:

The total ranges from 3 to 15. Forty years on, the authors stress that individual patients are best described by the three components, while the total is better suited to describing groups [13]. "E2 V3 M5" tells the receiving team more than "GCS 10".

Calculator: Glasgow Coma Scale.

9. CHA₂DS₂-VA for atrial fibrillation

New AF is a common ED finding. The 2024 ESC guideline uses CHA₂DS₂-VA, without the sex criterion: OAC is recommended at a score of 2 or more and should be considered at 1 [14]. Full explainer: CHA₂DS₂-VA vs CHA₂DS₂-VASc.

Calculator: CHA₂DS₂-VA.

10. HAS-BLED: bleeding risk in context

HAS-BLED estimates one-year major bleeding risk on anticoagulation [15]. The 2024 ESC guideline does not recommend any specific bleeding score and says such scores should not be used to withhold anticoagulation. The goal is to find and treat modifiable risk factors [14].

Calculator: HAS-BLED.

Bonus: lab calculators you will use often

• Anion gap in metabolic acidosis
• Corrected calcium with low albumin
• eGFR (CKD-EPI) and Cockcroft-Gault creatinine clearance

Five rules for using scores well

1. Scores estimate probability. They do not make diagnoses or replace examination.
2. Mind the population. A score validated in hospital patients may behave differently in primary care or in nursing home residents [1].
3. Repeat snapshots. Physiology changes within hours. In pneumonia, many patients who later needed intensive care had normal blood pressure at presentation and became hypotensive within 24 hours [1].
4. Use each score for its intended job. qSOFA is not a screening tool; HAS-BLED is not a veto.
5. Document the components. Individual values often matter more downstream than the total.

Bottom line

These ten scores cover most situations you will meet in the emergency department and in exams. Memorising points matters less than knowing what each score was designed for and what current guidelines say about it.

Medelix can help you look up guideline statements about a score quickly, with citations you can open and verify.

Sources

1. Ewig S, Kolditz M, Pletz M, et al. S3-Leitlinie Behandlung von erwachsenen Patienten mit ambulant erworbener Pneumonie – Update 2021 [German S3 guideline on adult community-acquired pneumonia]. AWMF register no. 020-020. PDF, AWMF register
2. Lim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003;58(5):377–382. doi:10.1136/thorax.58.5.377 · PMC1746657
3. Wells PS, Anderson DR, Rodger M, et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer. Thromb Haemost. 2000;83(3):416–420. doi:10.1055/s-0037-1613830
4. Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J. 2020;41(4):543–603. doi:10.1093/eurheartj/ehz405
5. American College of Cardiology. 2019 ESC Guidelines for the Diagnosis and Management of Acute PE (summary). 2020. acc.org
6. Backus BE, Six AJ, Kelder JC, et al. A prospective validation of the HEART score for chest pain patients at the emergency department. Int J Cardiol. 2013;168(3):2153–2158. doi:10.1016/j.ijcard.2013.01.255
7. Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC Guidelines for the management of acute coronary syndromes. Eur Heart J. 2023;44(38):3720–3826. doi:10.1093/eurheartj/ehad191
8. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801–810. doi:10.1001/jama.2016.0287 · PMC4968574
9. Evans L, Rhodes A, Alhazzani W, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Crit Care Med. 2021;49(11):e1063–e1143. doi:10.1097/CCM.0000000000005337 · SCCM overview
10. Royal College of Physicians. National Early Warning Score (NEWS) 2. rcp.ac.uk
11. NHS Greater Glasgow and Clyde. NEWS2 Guideline (based on RCP 2017). 2020. PDF
12. Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet. 1974;2(7872):81–84. doi:10.1016/s0140-6736(74)91639-0
13. Teasdale G, Maas A, Lecky F, et al. The Glasgow Coma Scale at 40 years: standing the test of time. Lancet Neurol. 2014;13(8):844–854. doi:10.1016/S1474-4422(14)70120-6
14. Van Gelder IC, Rienstra M, Bunting KV, et al. 2024 ESC Guidelines for the management of atrial fibrillation. Eur Heart J. 2024;45(36):3314–3414. doi:10.1093/eurheartj/ehae176
15. Pisters R, Lane DA, Nieuwlaat R, et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest. 2010;138(5):1093–1100. doi:10.1378/chest.10-0134