NICE NG51: recognising and managing suspected sepsis

Who it applies to

It applies to anyone with suspected sepsis in primary care, ambulance services, emergency departments and hospital wards, including pregnant women, children and neonates. It does not cover sepsis in patients already established on intensive care for another critical illness, and it does not set out detailed antibiotic choices beyond general principles.

The guideline in brief

Sepsis is the body's dysregulated response to infection, causing organ dysfunction that can progress to shock and death within hours if untreated. Because early signs can be subtle and mimic ordinary infection, NICE sets out a structured approach to make sure at-risk patients are not missed. The pathway starts with asking whether any patient with suspected infection could have sepsis, then stratifying risk using clinical criteria that look at behaviour, breathing, circulation and urine output. For adults, the 2024 update also uses the NEWS2 score alongside these high-risk criteria to decide how urgently antibiotics are needed: the sickest patients, and anyone with a clear bacterial source, are treated within an hour, while adults with high-risk criteria but a lower NEWS2 and an unclear cause can be investigated for up to 3 hours before starting antibiotics, to avoid unnecessary broad-spectrum use. Lower risk patients still need safety-netting advice and a clear plan for reassessment, because sepsis can evolve quickly. The guideline also covers how care should differ between community and hospital settings and gives separate risk criteria for children and for pregnant or recently pregnant women.

At a glance

• Think 'could this be sepsis' in any patient with signs of infection and new organ dysfunction or a marked change in behaviour.
• Use structured risk stratification criteria to classify patients as high or moderate-to-low risk of severe illness or death from sepsis; for adults, the 2024 update also uses the NEWS2 score alongside these criteria to decide how urgently antibiotics should be started.
• Patients identified as high risk need to be seen by a senior clinician promptly and have treatment started according to the urgency band they fall into.
• Give intravenous broad-spectrum antibiotics within 1 hour to children, pregnant or postpartum women, and adults with a NEWS2 score of 7 or more or a clear source of bacterial infection; adults with high-risk criteria but a NEWS2 of 0 to 6 and an unclear diagnosis can be safely investigated for up to 3 hours before starting antibiotics.
• Give an intravenous fluid bolus of crystalloid to high-risk adults with signs of hypoperfusion or shock, then reassess response before giving more.
• Measure serum lactate and give oxygen if indicated as part of the initial high-risk bundle of care.
• Use separate age-specific and pregnancy-specific risk criteria for children and for pregnant or postpartum women, because normal physiology differs.
• Give safety-netting information to patients discharged from any setting, explaining what worsening symptoms to watch for and when to seek urgent help.

Initial recognition

The first step everywhere, from a telephone triage call to a ward round, is actively considering sepsis in anyone with a possible infection.

• Ask whether a patient with signs or symptoms of infection also has any new alteration in mental state, breathing, circulation, or reduced urine output.Why: These are the earliest clinical clues that infection may be causing organ dysfunction rather than remaining localised.
• Consider sepsis in anyone who appears or is reported to be more unwell than expected for their apparent infection, including non-specific presentations in the very young, very old, or immunosuppressed.Why: Atypical presentation is common in these groups and delays recognition if clinicians wait for classic signs.
• Use a structured risk assessment at every contact point, including primary care, ambulance handover and emergency department triage, not only once on admission.Why: Risk can escalate between assessments, so recognition has to be repeated, not a one-off checkbox.

Risk stratification

Once sepsis is suspected, patients are sorted into risk categories that drive how urgently they are treated; in adults, the NEWS2 early warning score is combined with high-risk criteria to set the exact timeframe for antibiotics.

• Classify patients using criteria covering level of consciousness, respiratory rate and effort, heart rate, blood pressure, skin appearance, and urine output, adapted for adults, children and pregnant women.Why: Looking across several organ systems catches deterioration that a single vital sign might miss.
• Treat anyone meeting high-risk criteria as a medical emergency requiring immediate senior review.Why: High-risk criteria identify patients at significant risk of death from sepsis if treatment is delayed.
• In adults meeting high-risk criteria, use the NEWS2 score to decide the pace of antibiotic treatment: a NEWS2 of 7 or more, or an obvious bacterial focus, means antibiotics within 1 hour, while a NEWS2 of 0 to 6 with an unclear cause allows up to 3 hours of focused assessment first.Why: This lets clinicians investigate briefly in less acutely unwell adults rather than giving antibiotics to everyone who meets only broad high-risk criteria, reducing unnecessary antimicrobial use.
• Patients who do not meet high-risk criteria but have any concerning features are placed in a moderate-to-low risk category needing review and a clear safety net rather than discharge without follow-up.Why: These patients can still deteriorate, so they need a monitoring plan even if immediate escalation is not required.

Immediate management of high-risk patients

High-risk patients need a fast bundle of assessment and treatment, with the exact timing for antibiotics set by how unwell they are.

• Carry out venous blood tests including lactate, blood cultures, full blood count, and renal function as soon as possible after identifying high risk.Why: Lactate and culture results guide how severe the physiological derangement is and target antibiotic therapy.
• Give intravenous broad-spectrum antibiotics within 1 hour to children, pregnant or postpartum women, and adults with a NEWS2 of 7 or more or an identified bacterial source; in adults with high-risk criteria, a NEWS2 of 0 to 6 and an unclear diagnosis, antibiotics can be withheld for up to 3 hours while investigations clarify the picture.Why: Immediate antibiotics clearly benefit the sickest patients, while a short, structured delay in less acutely unwell adults with an unclear cause avoids unnecessary broad-spectrum use without increasing risk.
• Give an intravenous crystalloid fluid bolus to adults with hypotension or other signs of hypoperfusion, then reassess clinical response before further boluses.Why: Fluid resuscitation supports circulation while avoiding fluid overload from unmonitored repeated boluses.
• Give supplemental oxygen to maintain adequate saturation in line with usual target ranges for the patient's clinical state.Why: Tissue oxygen delivery is already compromised in sepsis, so hypoxaemia must be corrected promptly.
• Arrange escalation to critical care review for any high-risk patient not responding to initial treatment.Why: Non-response to initial resuscitation signals a need for higher-level monitoring and organ support.

Management of moderate-to-low risk patients

These patients need careful judgement rather than automatic discharge, because risk can still evolve.

• Carry out a clinical review, including consideration of blood tests such as lactate, if there is diagnostic uncertainty.Why: Some patients in this category still have early organ dysfunction that blood results can reveal before it becomes clinically obvious.
• Document a clear plan for reassessment, including who is responsible and the timeframe, before the patient leaves the point of care.Why: Without an explicit plan, early deterioration can be missed because no one is tasked with checking.
• Give verbal and written safety-netting advice describing specific symptoms that should prompt urgent return.Why: Patients and carers need actionable instructions since sepsis can progress rapidly after initial assessment.

Special populations

Children and pregnant or recently pregnant women need separate consideration because normal vital signs differ from the general adult population, and the NEWS2-based 3-hour antibiotic window does not apply to them.

• Use age-banded risk criteria for children, since normal heart rate, respiratory rate and blood pressure vary markedly with age.Why: Applying adult thresholds to children would miss or wrongly flag abnormal physiology.
• Give antibiotics within 1 hour to any child meeting high-risk criteria, rather than applying the adult 3-hour pathway.Why: Children can deteriorate faster and less predictably than adults, so the more cautious 1-hour standard is kept for them.
• Consider sepsis in any pregnant or postpartum woman with unexplained illness, fever, or an unusually unwell appearance, using pregnancy-specific risk criteria, and give antibiotics within 1 hour if she meets high-risk criteria.Why: Normal pregnancy physiology, including a raised baseline heart rate and lower blood pressure, can mask or mimic sepsis signs, so the same cautious 1-hour standard applies as for children.
• Have a lower threshold for senior obstetric and microbiology involvement in peripartum women with suspected sepsis.Why: Maternal sepsis can deteriorate very quickly and carries risk to both mother and baby.

Information, communication and safety-netting

Sepsis care depends on clear communication between clinicians and with patients and families at every transition of care.

• Explain to patients and families that sepsis is a possibility, what is being done, and what warning signs to report.Why: Informed patients and carers can act quickly if deterioration occurs after a clinical encounter ends.
• Hand over risk category, NEWS2 score where relevant, and management plan clearly at every transfer of care, including between ambulance and emergency department, and between wards.Why: Information loss at handover is a recognised cause of delayed recognition and treatment.
• Provide written safety-netting information on discharge describing when and how to seek urgent review.Why: Written information reduces the chance that verbal safety-netting advice is forgotten under stress.

Key numbers

Common pitfalls

• Assuming all adults with high-risk sepsis criteria need antibiotics within 1 hour; the 2024 update allows up to 3 hours in those with a NEWS2 of 0 to 6 and an unclear diagnosis, to reduce unnecessary antibiotic use.
• Relying on high-risk criteria alone without checking the NEWS2 score in adults; the score now determines whether the 1-hour or 3-hour antibiotic timeframe applies.
• Assuming a normal temperature rules out sepsis; fever is not required for sepsis and some patients, especially the very old, present hypothermic.
• Discharging moderate-to-low risk patients without a documented reassessment plan or written safety-netting advice; always give both.
• Using the same vital sign thresholds, or the adult 3-hour antibiotic window, for children; children and pregnant women keep the 1-hour standard and age- or pregnancy-appropriate risk criteria.
• Missing atypical presentations in pregnant women, where normal physiological changes can mask early warning signs; keep a lower threshold for suspicion peripartum.

What is new in this edition

• The 2024 update removed the blanket requirement for antibiotics within 1 hour in all high-risk adults.
• Adults meeting high-risk criteria but with a NEWS2 of 0 to 6 and an unclear diagnosis can now be investigated for up to 3 hours before starting antibiotics, aiming to reduce unnecessary broad-spectrum antibiotic use.
• The NEWS2 score is now explicitly incorporated into the adult pathway to decide between the 1-hour and 3-hour antibiotic timeframes.

Practice points for students

• Sepsis is a clinical emergency defined by organ dysfunction from infection, not simply the presence of infection with fever.
• In adults, the NEWS2 score combined with high-risk criteria now determines whether antibiotics are needed within 1 hour or can wait up to 3 hours for an unclear diagnosis.
• Children and pregnant or postpartum women always stay on the 1-hour antibiotic standard, regardless of NEWS2.
• Every discharged patient with suspected but lower-risk sepsis needs a reassessment plan and written safety-netting advice.
• Delays to antibiotics and fluids in the sickest patients remain the most preventable cause of avoidable harm in sepsis care.

Check yourself

Abbreviations and tools

NICE

National Institute for Health and Care Excellence, the UK body that produces this guideline.

NG51

The guideline's reference number within the NICE guidance series.

NEWS2

National Early Warning Score 2, a bedside score based on vital signs used to track how physiologically unwell a patient is.

Condition

Other guidelines on this topic

• Surviving Sepsis Campaign: international guidelines for management of sepsis and septic shock 2026Surviving Sepsis Campaign2026Official guideline

Independent educational summary written by the WhiteCoat Pro editorial team with AI assistance and checked by a second AI model. It does not reproduce the guideline text, tables or figures, and it is not affiliated with or endorsed by NICE. It is not medical advice: always read the original guideline before applying it to patients.