# CURB-65 Score (Pneumonia Severity)

Calculate the CURB-65 score to assess community-acquired pneumonia (CAP) severity and guide the site of care. Each component scores 1 point: Confusion (new-onset disorientation), Urea > 7 mmol/L (BUN > 20 mg/dL), Respiratory rate ≥ 30/min, Blood pressure (systolic < 90 OR diastolic ≤ 60 mmHg), and Age ≥ 65. Range 0–5. Interpretation: 0–1 low risk (likely outpatient; 30-day mortality ~1.5–2.4%), 2 moderate (consider admission or supervised discharge, ~9.2%), 3–5 high risk (hospital admission; consider ICU for 4–5; mortality rises to ~57% at score 5). Endorsed by the British Thoracic Society. Derived from Lim et al. 2003 (Thorax). Not medical advice.

> Canonical page: https://elysiatools.com/en/tools/curb-65-score

- **Category:** Health

- **Keywords:** CURB-65, CURB65, pneumonia, community-acquired pneumonia, CAP, severity, BTS, respiratory, infection, mortality

## Overview

The CURB-65 calculator scores community-acquired pneumonia severity from 0 to 5 using confusion, urea, respiratory rate, blood pressure, and age. Use the result to support decisions about outpatient care, observation, hospital admission, or possible ICU consideration; it is not medical advice.

## Inputs

- **New-onset confusion** (checkbox): New-onset mental disorientation (any acute confusion). +1.
- **Urea > 7 mmol/L (BUN > 20 mg/dL)** (checkbox): Serum urea > 7 mmol/L (equivalent to BUN > 20 mg/dL). +1.
- **Respiratory rate ≥ 30/min** (checkbox): Respiratory rate ≥ 30 breaths per minute. +1.
- **BP: systolic < 90 or diastolic ≤ 60 mmHg** (checkbox): Systolic BP < 90 mmHg OR diastolic BP ≤ 60 mmHg. +1.
- **Age ≥ 65 years** (checkbox): Age 65 years or older. +1.

## When to use

- Assess the severity of suspected community-acquired pneumonia in adults.
- Review whether a low, moderate, or high CURB-65 risk category may support the planned site of care.
- Document the five CURB-65 criteria consistently during clinical assessment.

## How it works

- Select each criterion that applies: new-onset confusion, urea above 7 mmol/L or BUN above 20 mg/dL, respiratory rate of at least 30 per minute, low blood pressure, and age 65 or older.
- The calculator assigns 1 point for each selected criterion.
- It adds the points to produce a total score from 0 to 5.
- The result reports the corresponding low-, moderate-, or high-risk category and its stated care interpretation.

## Use cases

- Emergency and acute-care assessment of adults with community-acquired pneumonia.
- Clinical documentation of pneumonia severity and site-of-care considerations.
- Teaching and review of the CURB-65 scoring criteria for healthcare learners.

## Frequently asked questions

### What does the CURB-65 score measure?

It estimates the severity of community-acquired pneumonia and helps inform the appropriate site of care.

### What are the five CURB-65 criteria?

Confusion, urea above 7 mmol/L or BUN above 20 mg/dL, respiratory rate at least 30 per minute, low blood pressure, and age 65 or older.

### What is the CURB-65 score range?

The total ranges from 0 to 5, with 1 point assigned for each criterion present.

### How is a score of 2 interpreted?

A score of 2 is classified as moderate risk; admission or supervised discharge should be considered.

### Is CURB-65 a substitute for clinical judgment?

No. It is a decision-support score and does not replace clinical assessment or medical advice.

## Related tools

- [Apgar Score (Newborn 1 & 5 min)](https://elysiatools.com/en/tools/apgar-score): Calculate the Apgar score to assess newborn condition at 1 minute and 5 minutes after birth. Five signs are each scored 0–2 at both time points: Appearance (skin color), Pulse (heart rate), Grimace (reflex irritability), Activity (muscle tone), and Respiration. Each time point totals 0–10. Interpretation: 7–10 reassuring; 4–6 moderately abnormal (may need assistance); 0–3 critically low (immediate resuscitation). The tool reports both the 1-min and 5-min scores, the change (delta), and per-time-point interpretation. A 5-min score, and especially the change from 1 to 5 min, indicates response to resuscitation; persistent low 5-min scores warrant continued resuscitation and reassessment at 10 min. Derived from Apgar 1953, reaffirmed by ACOG/AAP. The Apgar is a physiologic snapshot at a moment in time and is not, by itself, a marker of asphyxia or long-term neurologic outcome. Not medical advice.
- [Child-Pugh Score (Cirrhosis Severity)](https://elysiatools.com/en/tools/child-pugh-score): Calculate the Child-Pugh score to grade chronic liver disease / cirrhosis severity and estimate perioperative mortality. Five parameters scored 1–3 each (total 5–15): Total bilirubin (<2 mg/dL =1, 2–3 =2, >3 =3) — supports mg/dL or µmol/L input (auto ÷17.1); Serum albumin (>3.5 g/dL =1, 2.8–3.5 =2, <2.8 =3); INR (<1.7 =1, 1.7–2.3 =2, >2.3 =3); Ascites (absent =1, slight/controlled =2, moderate–severe =3); Hepatic encephalopathy (none =1, grade I–II =2, grade III–IV =3). Classes: A (5–6) well-compensated (1-y ~100%, 2-y ~85%); B (7–9) significant compromise (1-y ~80%, 2-y ~60%); C (10–15) decompensated (1-y ~45%, 2-y ~35%). Derived from Pugh et al. 1973 (Br J Surg) and the original Child-Turcotte classification. Not medical advice.
- [Dose by Body Surface Area Calculator (BSA = √(H·W/3600))](https://elysiatools.com/en/tools/dose-by-body-surface-area): Calculate an individualized drug dose from body surface area using the Mosteller formula: BSA (m²) = √(Height(cm) · Weight(kg) / 3600), then Dose = Drug_dose_per_m² × BSA. BSA is the recommended normalization for many cytotoxic and pediatric regimens because drug clearance scales more linearly with BSA than with body weight across patients of different sizes. Also reports the standard adult dose at the reference adult BSA of 1.73 m² for comparison. Valid only for linear drug clearance — BSA dosing does not apply to saturable (Michaelis-Menten) pathways. Not medical advice.
- [Dosing Interval Designer (Peak/Trough Ratio)](https://elysiatools.com/en/tools/dosing-interval-designer): Design the dosing interval τ from the steady-state peak/trough concentration ratio. For one-compartment linear kinetics at steady state, the peak-to-trough ratio over one interval is P = Cmax,ss / Cmin,ss = e^(kτ) where k = ln2 / t½. Mode A: given a target peak/trough ratio, solve for the dosing interval τ = ln(P) · t½ / ln2. Mode B: given a chosen interval τ, compute the resulting peak/trough ratio P = e^(kτ). Note: P reflects fluctuation WITHIN one interval and is NOT the accumulation index (R = 1/(1-e^(-kτ))). Valid only for linear one-compartment kinetics, steady state, fixed dose and interval. Not medical advice.
- [Drug Clearance Calculator (CL)](https://elysiatools.com/en/tools/drug-clearance-calculator): Calculate drug clearance CL in two modes. (A) Definition: CL = elimination rate / concentration, valid for any pharmacokinetic model. (B) Linear first-order: CL = k · Vd (or derive k from t½ via k = ln2 / t½). Also reports the relationship t½ = 0.693 · Vd / CL. CL is a definitional parameter independent of Vd. Linear mode applies only to first-order elimination — NOT to Michaelis-Menten drugs (phenytoin, high-dose ethanol). Reference: theophylline CL ≈ 2.8 L/h in a 70 kg non-smoking adult. Not medical advice.
- [Elimination Rate Constant Calculator (k = ln2 / t½)](https://elysiatools.com/en/tools/elimination-rate-constant): Convert an elimination half-life to the first-order elimination rate constant: k = ln2 / t½ = 0.693 / t½. Also reports the fraction of drug remaining after 1/2/3/4/5 half-lives (50%, 25%, 12.5%, 6.25%, 3.125%), the number of half-lives required to reach steady state (≈4 for 94%, ≈5 for 97%), and the time to ~99% elimination (≈6.64 half-lives). Valid only for first-order (linear) elimination — NOT for zero-order or Michaelis-Menten kinetics (phenytoin, high-dose ethanol, high-dose aspirin). Not medical advice.
- [IV Infusion Rate Calculator (R₀ = Css · CL)](https://elysiatools.com/en/tools/iv-infusion-rate-calculator): Calculate the continuous IV infusion rate that maintains a target steady-state plasma concentration: R₀ = Css · CL, where Css is the target concentration and CL is clearance. At steady state, the infusion rate equals the elimination rate. If the IV solution concentration (mg/mL) is provided, the tool additionally derives the infusion-pump delivery rate in mL/h, which is what the pump is actually set to in clinical practice. This is an IV-only tool — bioavailability F is not applicable. Reaching steady state requires approximately 4–5 half-lives. Not medical advice.
- [MELD-Na Score (Sodium-Modified MELD)](https://elysiatools.com/en/tools/meld-na-score): Calculate the UNOS/OPTN MELD-Na score — the sodium-modified MELD used for adult liver transplant allocation in the US from January 2016 until superseded by MELD 3.0 in July 2023. First compute the base MELD(i) (same formula as MELD, clamped 6–40). If MELD(i) > 11: MELD-Na = MELD(i) + 1.32·(137 − Na) − 0.033·MELD(i)·(137 − Na), with sodium clamped to 125–137 mmol/L. If MELD(i) ≤ 11, MELD-Na = MELD(i) (no sodium adjustment). The result is rounded and clamped to 6–40. Rationale: hyponatremia (Na < 137) predicts worse waitlist mortality beyond what MELD(i) captures, so the score is inflated; the interaction term scales the sodium penalty down at very high MELD(i). Derived from Kim/Biggins 2008 (NEJM) and UNOS/OPTN policy. Not medical advice.

## Samples

- [Web Image Processing Python Samples](https://elysiatools.com/en/samples/web-image-processing-python): Web Python image processing examples using PIL/Pillow including reading, saving, resizing, and format conversion
- [Android Image Processing Java Samples](https://elysiatools.com/en/samples/android-image-processing-java): Android Java image processing examples including reading/saving images, scaling, and format conversion
- [Android Image Processing Kotlin Samples](https://elysiatools.com/en/samples/android-image-processing-kotlin): Android Kotlin image processing examples including reading/saving images, scaling, and format conversion
- [Web Image Processing Rust Samples](https://elysiatools.com/en/samples/web-image-processing-rust): Web Rust image processing examples including image read/save, scaling, and format conversion

## Related content

- [Health Tools](https://elysiatools.com/en/hubs/health-utility): Explore 29 health tools for utility workflows and compare closely related utilities quickly.
- [Meditation, Sleep, and Relaxation Tools](https://elysiatools.com/en/hubs/meditation-sleep-relaxation): Compare guided meditation, breathing routines, PMR, sleep-cycle planning, stress self-checks, and supporting audio tools in one hub for calmer daily routines.
- [Endurance Training Pace, Heart Rate, and Effort Tools](https://elysiatools.com/en/hubs/endurance-training-metrics): Compare pace calculators, heart-rate zone tools, VO2 max estimates, cycling power, calorie burn, and training-load metrics in one hub for running, cycling, swimming, and triathlon planning.
- [Nutrition, Body Composition, and Sleep Calculators](https://elysiatools.com/en/hubs/nutrition-body-composition-sleep-calculators): Calculate daily macros, protein targets, lean body mass, TDEE and BMR, hydration and sweat rate, walking calorie burn, and optimal sleep-wake times with step-by-step body-metric tools.