How A&E triage actually works (and why someone who arrived after you got seen first)

When you arrive at A&E, a triage nurse sees you within ~15 minutes and assigns you a clinical urgency category from one to five. The most urgent patient in the department is always seen first, regardless of when they arrived. That is why the order can look unfair from the waiting room, and why the ‘just chest pain’ patient who walked in 20 minutes after you might already be in resus.

Almost every UK adult A&E uses the Manchester Triage System (MTS), developed in the late 1990s by the Manchester Triage Group. It is built around ‘flow charts’ — for each presenting complaint (chest pain, abdominal pain, head injury, fever, etc.) the triage nurse works through a series of yes/no questions until the patient is assigned one of five categories.

MTS is deliberately conservative: when in doubt, the nurse picks the higher-urgency category. The system is internationally validated and used in over 30 countries.

Most A&E patients are Yellow or Green. Red and Orange combined account for roughly 15 % of attendances. The 4-hour NHS standard applies to the entire journey (arrival → discharge or admission), not just ‘time to be seen’.

1. Reception & booking-in. Your name, date of birth and presenting complaint are recorded. NHS number is helpful but not required.
2. Initial observations. Pulse, blood pressure, temperature, breathing rate, oxygen saturation, sometimes blood sugar. Combined into a National Early Warning Score (NEWS2).
3. Triage interview. Triage nurse uses MTS to assign a category.
4. Streaming. You are sent to majors, minors, paediatric A&E, the UTC stream, or directly to a specialty (e.g. medical assessment unit).
5. Wait for clinician. A&E doctor or advanced clinical practitioner sees you in order of clinical priority.
6. Investigation, treatment, decision. Bloods, X-rays, ECGs, CT scans, treatment, and a discharge or admission decision.

The single most common A&E complaint isn’t the long wait itself — it’s the perceived unfairness of seeing someone walk in 20 minutes after you and disappear into a cubicle while you’re still waiting. There are five legitimate reasons:

• They were triaged into a higher category — Red, Orange or top of Yellow.
• They arrived by ambulance and were pre-alerted (cardiac, stroke or sepsis pathway).
• They were on a specific clinical pathway — e.g. suspected sepsis, paediatric, or a known oncology or transplant patient with an agreed protocol.
• They needed a specific bed or specialist that just became available.
• Their condition deteriorated in the waiting room and they were re-triaged.

None of those reasons get communicated to the rest of the waiting room, which is why it can feel arbitrary. It isn’t.

By the time you are discharged from A&E, one of four things has happened:

• Sent home with a self-care plan. Most common (~70 % of A&E attendances).
• Sent home with a prescription (typically antibiotics or pain relief).
• Referred to a same-day specialty clinic — fracture clinic, ENT, ophthalmology, surgical assessment unit.
• Admitted to a hospital ward — usually after an extra wait for a bed, which is the biggest drag on the 4-hour standard.

See our follow-up guide: After being seen at A&E.

The NHS Constitution and Royal College of Emergency Medicine standards give you specific rights when waiting in A&E:

• To be re-assessed if you feel worse. Ask a nurse — be specific about what has changed.
• To pain relief. If you are in significant pain you can ask for analgesia at any point — you don’t have to wait for the doctor.
• To food and water unless you are about to be operated on.
• To privacy when discussing personal information.
• To complain via the hospital’s PALS service if you feel your care fell below standard. Every hospital has a PALS office — staff will signpost you.