If there's one topic guaranteed to appear on your FRCEM SBA paper, it's sepsis. It sits squarely across SLO 1 (Complex/High-Risk Presentations) and SLO 3 (Resuscitation), and it's exactly the kind of subject the RCEM loves to test — not because the concept is hard, but because the guidelines keep moving and the exam rewards candidates who know the current version, not the one they learned as a foundation doctor.
This guide walks through sepsis and septic shock the way the FRCEM SBA actually tests it: current definitions, the exact numbers examiners hang questions on, and the specific traps that catch out candidates revising from outdated question banks.
What Counts as Sepsis in 2026 — Sepsis-3, Not SIRS
The single biggest trap in this topic area is relying on SIRS criteria. If you trained more than a few years ago, SIRS (temperature, heart rate, respiratory rate, white cell count) may still be sitting in your mental model as the definition of sepsis. It isn't anymore, and the SBA knows it.
Sepsis-3, the current internationally accepted definition, describes sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. The practical marker of that organ dysfunction in the ED is a rise in the Sequential Organ Failure Assessment (SOFA) score of 2 points or more from baseline, in the context of confirmed or suspected infection.
Why does this matter for exam technique? Because a question bank still testing SIRS-based answers will occasionally point you toward the wrong option. If a stem describes a patient who's tachycardic and pyrexial but shows no evidence of organ dysfunction, the "correct" SBA answer under Sepsis-3 may be to treat this as a lower-risk presentation rather than escalating straight to full sepsis pathway activation — a distinction SIRS-based thinking would miss entirely.
Septic Shock — The Exact Numbers Examiners Test
Septic shock is a subset of sepsis, and the exam expects precision here, not a general sense of "really sick with infection." The current definition requires all of the following:
Sepsis (confirmed infection plus organ dysfunction, as above)
Persistent hypotension requiring vasopressors to maintain a mean arterial pressure (MAP) of 65 mmHg or above
A serum lactate greater than 2 mmol/L
Both criteria present despite adequate volume resuscitation
That last point is the one candidates most often skip when answering under time pressure. A patient who's hypotensive and has a raised lactate before any fluid has been given doesn't yet meet the septic shock definition — they're hypoperfused, but the diagnosis depends on the picture persisting after resuscitation. Examiners build distractor answers around this exact sequencing.
NEWS2 and Early Recognition in the ED
Before you even reach a sepsis diagnosis, the SBA tests your ability to recognise deterioration using the National Early Warning Score 2 (NEWS2), the Royal College of Physicians' standardised early warning tool used across UK EDs and wards.
NEWS2 scores respiration rate, oxygen saturation, supplemental oxygen use, systolic blood pressure, pulse rate, level of consciousness, and temperature. A high aggregate score — particularly a score of 7 or more, or any single parameter scoring 3 — should trigger urgent senior review and consideration of the sepsis pathway.
The exam trap here is treating NEWS2 as optional or as something used only on the wards. In current RCEM-aligned practice, NEWS2 is explicitly part of ED early recognition, and SBA stems often embed a full set of vital signs specifically so you can calculate or interpret the score rather than eyeballing "looks unwell."
The Sepsis Six — Deliver Within the Hour
Once sepsis is suspected, the Sepsis Six remains the backbone of initial management, championed by the UK Sepsis Trust and aligned with NICE NG51. It's built around three actions to give and three actions to take, all within the first hour of recognition.
Give:
High-flow oxygen to maintain target saturations
IV fluids — typically a crystalloid bolus, following the 30 mL/kg guidance for hypoperfusion
IV broad-spectrum antibiotics, guided by local policy and likely source
Take:
Blood cultures before antibiotics, where this doesn't cause delay
Serum lactate
Accurate urine output monitoring
The SBA loves to test the ordering here. A classic distractor puts antibiotics before blood cultures as the "correct" first step, or delays antibiotics until cultures are formally sent to the lab. The actual expectation is that cultures are taken quickly, but antibiotic administration should not be delayed waiting for that process to be perfect — the one-hour bundle is a package, not a strict sequence with cultures as a gatekeeper.
NICE NG51 Risk Stratification — High vs Moderate Risk Criteria
NICE NG51 (Sepsis: recognition, diagnosis and early management) provides the risk stratification tool examiners frequently lift stems directly from. High-risk criteria include:
Objective evidence of new altered mental state
Respiratory rate of 25 or more per minute, or new need for oxygen to maintain saturations above 92%
Systolic BP of 90 mmHg or less, or a drop of more than 40 mmHg from normal
Heart rate over 130 per minute
Not passed urine in the last 18 hours, or urine output less than 0.5 mL/kg/hour
Mottled or ashen appearance, cyanosis, or non-blanching rash
Recent chemotherapy
A patient meeting any single high-risk criterion should trigger immediate senior clinician review and Sepsis Six initiation. Moderate-to-low risk criteria (relative tachycardia, impaired mobility, immunosuppression without high-risk features) warrant a more measured but still structured response — repeat observations and clear safety-netting rather than automatic escalation. Distinguishing high-risk from moderate-risk stems is a frequent SBA discriminator between candidates who know the tool and those who are guessing from clinical gestalt.
Fluid Resuscitation and Vasopressors — What the SBA Actually Tests
Current Surviving Sepsis Campaign guidance recommends at least 30 mL/kg of IV crystalloid within the first three hours for patients with sepsis-induced hypoperfusion or septic shock. The SBA will test your ability to calculate this for a given patient weight, and will sometimes offer a lower "rounded down" volume as a distractor.
If hypotension persists despite this fluid resuscitation and the MAP remains below 65 mmHg, the next step is vasopressor support — noradrenaline is the first-line agent in current UK practice. A frequent SBA trap presents a patient who is already fluid-replete and hypotensive, with an answer option offering "further fluid boluses" as the correct next step. In a genuinely fluid-resistant picture, the correct answer is escalation to vasopressors, not repeated fluid challenges that risk overload without addressing the underlying vasodilation.
Antibiotics — Timing and Source Control Traps
Broad-spectrum IV antibiotics should be given within one hour of recognising sepsis, guided by local antimicrobial policy and the likely source of infection. The exam occasionally tests source-specific reasoning — for example, recognising that a suspected intra-abdominal source needs surgical or interventional radiology input for source control alongside antibiotics, since antibiotics alone won't resolve an undrained collection or perforation.
A subtler trap involves patients with penicillin allergy or renal impairment — the SBA sometimes expects you to identify that a "correct" broad-spectrum choice needs adjusting for these factors, testing safe prescribing alongside sepsis knowledge rather than sepsis knowledge in isolation.
Common FRCEM SBA Traps in Sepsis Questions
Using SIRS criteria instead of Sepsis-3/SOFA-based organ dysfunction to identify sepsis
Treating septic shock as defined by hypotension alone, without checking the "despite adequate fluid resuscitation" qualifier
Sequencing antibiotics after cultures are formally processed, rather than giving both promptly within the bundle
Choosing further fluid boluses as the answer when a patient is already fluid-resistant and needs vasopressors
Missing NICE NG51 high-risk criteria embedded in a stem's vital signs and social history
In the final week before your exam, it's worth deliberately re-reading old question bank explanations with this list in hand—outdated banks are a common source of exactly these errors.
Worked SBA-Style Practice Question
A 68-year-old man presents with a two-day history of fever and confusion, with a background of a recent urinary catheter change. Observations: HR 128, BP 84/52, RR 26, SpO2 91% on air, temperature 38.9°C, GCS 14. Lactate returns at 3.8 mmol/L. He has received 2 litres of crystalloid over the past 90 minutes with no improvement in blood pressure.
What is the most appropriate next step?
A. Administer a further 1-litre crystalloid bolus
B. Start noradrenaline infusion and arrange critical care review
C. Delay further intervention pending blood culture results
D. Discharge with oral antibiotics and safety-netting advice
E. Repeat lactate in 6 hours before escalating
The correct answer is B. This patient meets the criteria for septic shock — persistent hypotension and a lactate above 2 mmol/L despite adequate fluid resuscitation. The appropriate next step is vasopressor support and critical care involvement, not further fluid challenges (option A), which risk fluid overload without correcting the underlying problem.
FAQs
Is SIRS still tested in the FRCEM SBA sepsis questions?
No, current SBA questions are based on the Sepsis-3 definition and SOFA-based organ dysfunction. Relying on SIRS criteria alone can lead you to the wrong answer.
What defines septic shock for exam purposes?
Sepsis plus persistent hypotension needing vasopressors to keep MAP at 65 mmHg or above, plus a lactate over 2 mmol/L, despite adequate fluid resuscitation.
How much fluid should be given in the first hour for suspected septic shock?
Current guidance recommends at least 30 mL/kg of IV crystalloid within the first three hours for hypoperfusion or septic shock, with reassessment throughout.
When should vasopressors be started instead of more fluids?
When hypotension persists after adequate crystalloid resuscitation, noradrenaline is the first-line vasopressor rather than continued fluid boluses.
What is the Sepsis Six and why does it matter for the exam?
It's the three-give, three-take bundle (oxygen, fluids, antibiotics; cultures, lactate, urine output) to be completed within one hour of recognising sepsis, and it's a frequent source of sequencing-based SBA questions.
Conclusion
Sepsis is one of those FRCEM topics where the underlying clinical reasoning is genuinely straightforward — the difficulty is entirely in knowing the current thresholds and definitions well enough to spot when a question bank is testing you on outdated material. Sepsis-3, NICE NG51, and the Sepsis Six aren't separate revision topics; they're one interconnected pathway, and the exam expects you to move between them fluently under time pressure.
If you want to test this knowledge properly before exam day, StudyFRCEM's question bank includes SLO-mapped, consultant-written sepsis and resuscitation scenarios built around the exact guideline versions covered here — so you're practising against current standards, not last decade's SIRS criteria.
Frequently Asked Questions
Is SIRS still tested in the FRCEM SBA sepsis questions?
No, current SBA questions are based on the Sepsis-3 definition and SOFA-based organ dysfunction. Relying on SIRS criteria alone can lead you to the wrong answer.
What defines septic shock for exam purposes?
Sepsis plus persistent hypotension needing vasopressors to keep MAP at 65 mmHg or above, plus a lactate over 2 mmol/L, despite adequate fluid resuscitation.
How much fluid should be given in the first hour for suspected septic shock?
Current guidance recommends at least 30 mL/kg of IV crystalloid within the first three hours for hypoperfusion or septic shock, with reassessment throughout.
When should vasopressors be started instead of more fluids?
When hypotension persists after adequate crystalloid resuscitation, noradrenaline is the first-line vasopressor rather than continued fluid boluses.
What is the Sepsis Six and why does it matter for the exam?
It's the three-give, three-take bundle (oxygen, fluids, antibiotics; cultures, lactate, urine output) to be completed within one hour of recognising sepsis, and it's a frequent source of sequencing-based SBA questions.