Quick answer: in adults with suspected sepsis in hospital, NICE uses the NEWS2 score to set the level of risk, and the level of risk sets how quickly antibiotics are needed. A NEWS2 score of 7 or more is high risk and needs broad-spectrum intravenous antibiotics within 1 hour. A score of 5 or 6 is moderate risk (antibiotics within 3 hours) and 1 to 4 is low risk (within 6 hours), which gives time to confirm the diagnosis and target treatment. Take blood cultures and a lactate early, and give fluids if the lactate is raised or the patient is hypotensive.
Sepsis is one of the most heavily tested topics in the MRCEM because it combines recognition, risk scoring and time-critical treatment. Questions usually give you a set of observations and ask what to do next, and how fast. This guide follows the NICE guideline on suspected sepsis in people aged 16 or over (NG253), which replaced the older NG51 in November 2025. In practice, always follow your local sepsis pathway and antibiotic policy.
What is sepsis?
Sepsis is life-threatening organ dysfunction caused by a dysregulated host response to infection. Septic shock is the most severe form: the patient needs vasopressors to keep the mean arterial pressure at 65 mmHg or above and has a lactate above 2 mmol/L despite adequate fluid resuscitation.
Think about sepsis in anyone with a possible infection who looks unwell, and remember that it may present without a fever. Older people, people who are immunosuppressed and those who have had recent surgery or an invasive procedure are at higher risk and often present atypically, for example with new confusion or a fall.
Risk stratification with NEWS2
NEWS2 scores seven items: respiratory rate, oxygen saturation, supplemental oxygen, systolic blood pressure, pulse, level of consciousness (including new confusion) and temperature. In acute hospital settings, NICE maps the total score to a level of risk of severe illness or death from sepsis:
| NEWS2 score | Risk level | Antibiotics |
|---|---|---|
| 7 or more | High | Broad-spectrum IV antibiotics within 1 hour |
| 5 or 6 | Moderate | Within 3 hours, once the diagnosis is clearer |
| 1 to 4 | Low | Within 6 hours, if a bacterial infection is confirmed or still suspected |
| 0 | Very low | Manage according to clinical judgement |
The clock starts when the NEWS2 score is calculated, for example at triage in the emergency department.
When the score underestimates the risk
NEWS2 supports clinical judgement and does not replace it. Treat the risk as higher than the score suggests in these situations:
- A score of 3 in any single parameter: this needs an urgent review by a clinician at FY2 level or above, who decides whether the patient should be moved up a risk level.
- Skin signs: a mottled or ashen appearance, cyanosis of the skin, lips or tongue, or a non-blanching rash point to high risk whatever the score.
- Deterioration or no improvement: a patient who gets worse, or whose score does not improve after initial treatment, should be re-evaluated as higher risk and escalated to a senior decision-maker.
NEWS2 is not validated in children or in pregnancy. NICE covers these groups in separate guidelines (NG254 for under 16s and NG255 for people who are pregnant or recently pregnant).
Initial investigations
For patients at high or moderate risk, send:
- Blood cultures, ideally before the first dose of antibiotics, as long as this does not delay treatment.
- Blood gas with lactate and glucose.
- Full blood count, CRP, urea and electrolytes, creatinine, liver function tests and a clotting screen.
Look for the source at the same time: urine dip and culture, chest X-ray, and other cultures or imaging guided by the history and examination.
Initial treatment
Antibiotics
High-risk patients get broad-spectrum intravenous antibiotics within 1 hour, chosen from the local policy for the likely source. For moderate and low risk patients, the extra time is there to make a diagnosis, so that antibiotics can be targeted or avoided if the cause is not bacterial. This balance between early treatment and antimicrobial stewardship is a common exam theme.
Intravenous fluids
Give fluids to high-risk patients with a lactate above 2 mmol/L or a systolic blood pressure below 90 mmHg. Use an isotonic crystalloid, give it as a bolus over 10 to 15 minutes and reassess after each bolus. NICE now recommends 250 ml boluses, with senior and critical care review if the patient has not responded after a total of 1,000 ml.
Oxygen, urine output and source control
- Give oxygen to keep saturations at 94 to 98%, or 88 to 92% in patients at risk of hypercapnic respiratory failure.
- Monitor urine output, with a catheter if needed.
- Find the source and control it early, for example by draining an abscess or removing an infected line. Involve the surgical team promptly if a surgical source is likely.
When to escalate
Discuss with critical care early if the patient has:
- a lactate above 4 mmol/L,
- hypotension that does not respond to fluid boluses, or
- no improvement within 1 hour of antibiotics and fluids.
These patients may need vasopressors, usually noradrenaline, and organ support.
Neutropenic sepsis
Suspect neutropenic sepsis in anyone who becomes unwell after recent systemic anticancer treatment. It is diagnosed with a temperature above 38°C, or other signs of sepsis, and a neutrophil count of 0.5 × 109/L or lower. Treat it as an emergency and give empirical antibiotics immediately, without waiting for the blood count.
Common exam traps
- Giving every patient antibiotics within 1 hour: the 1-hour target applies to high-risk patients. Moderate and low risk patients have 3 and 6 hours.
- Ignoring a single parameter score of 3: a total score of 3 or 4 can still need urgent review.
- Waiting for a fever: sepsis can present with a normal or low temperature, especially in older people.
- Using qSOFA or SIRS to screen: UK practice uses NEWS2 in adults.
- Delaying antibiotics for cultures: take cultures first where possible, but never at the cost of the 1-hour target.
- Applying NEWS2 to children or pregnant patients: it is not validated in either group.
Summary
- Use NEWS2 to set the risk level: 7 or more is high, 5 or 6 is moderate, 1 to 4 is low.
- Antibiotics within 1 hour for high risk, 3 hours for moderate risk and 6 hours for low risk.
- A single parameter score of 3, mottled skin, cyanosis or a non-blanching rash raise the level of concern.
- Send blood cultures and a lactate early. Give fluid boluses if the lactate is above 2 mmol/L or the systolic blood pressure is below 90 mmHg.
- Escalate to critical care for a lactate above 4 mmol/L or hypotension that does not respond to fluids.
Frequently asked questions
What NEWS2 score means high risk of sepsis?
A score of 7 or more. Patients with a lower score can still be high risk if they have a mottled or ashen appearance, cyanosis or a non-blanching rash, or if a clinician judges the risk to be higher.
How quickly should antibiotics be given in sepsis?
Within 1 hour for high-risk patients, within 3 hours for moderate risk and within 6 hours for low risk, counted from when the NEWS2 score is calculated.
What lactate level is significant in sepsis?
A lactate above 2 mmol/L is an indication for fluid resuscitation. A lactate above 4 mmol/L should prompt a critical care discussion.
Is qSOFA used in the UK?
No. NICE recommends NEWS2 to assess adults with suspected sepsis in acute hospital settings.
Next steps
Test yourself with our 20 free MRCEM SBA sample questions. For more, explore our Infectious disease resources and the sepsis lesson in the Resuscitation course, or see the full question bank and mock tests in our membership plans.
Clinical content checked against the NICE guideline on suspected sepsis in people aged 16 or over (NG253) on 3 October 2026. This article is for exam preparation. In clinical practice, always follow your local sepsis pathway and antibiotic policy.