How A&E Triage Works: Why You Might Wait While Others Go First

What is triage?

Triage is the process of sorting patients by clinical urgency so that the sickest are seen first. The word comes from the French trier, meaning to sort or sift. In an A&E department, triage happens within minutes of your arrival and determines your place in the clinical queue — which is separate from and more important than your place in the physical waiting room.

Understanding triage removes much of the frustration of A&E. When you see someone who arrived after you being called through first, it almost always means their clinical need is greater, not that the system has forgotten you. This guide explains exactly how the process works.

The triage assessment

When you arrive at A&E and complete registration, a triage nurse — typically a senior nurse with additional emergency assessment training — will see you. The national target is within 15 minutes of arrival, though this varies with department workload.

During triage, the nurse assesses:

Vital signs

• Blood pressure — using a cuff on your arm
• Heart rate (pulse) — measured at the wrist or by the blood-pressure machine
• Respiratory rate — how many breaths you take per minute, often counted by observation
• Temperature — using an ear or forehead thermometer
• Oxygen saturation — a small clip on your finger that measures how well your blood is carrying oxygen
• Blood glucose — if diabetes is suspected or relevant, a finger-prick test

These numbers are plotted against normal ranges to calculate an early warning score. The higher the score, the more abnormal your observations are, and the higher your clinical priority.

Symptoms and history

The nurse asks targeted questions:

• What happened and when did it start?
• Where is the pain and how severe is it (usually on a scale of 0 to 10)?
• Is the problem getting better, staying the same, or getting worse?
• What have you already tried (medication, ice, rest)?
• Do you have relevant medical history — for example, a heart condition if you have chest pain?
• What medications are you taking?
• Do you have any allergies?

Physical examination

The nurse may briefly examine the affected area — looking at a wound, feeling a swollen joint, listening to your chest — to gather enough information for categorisation. This is not the full clinical examination; that comes later when you see the treating clinician.

The five priority categories

Most UK A&E departments use the Manchester Triage System (MTS), which assigns one of five priority levels. Some departments use a different system, but the principle is the same.

Category 1 — Immediate (Red)

Target: seen immediately, within 0 minutes.

This is reserved for patients whose life is at immediate risk: cardiac arrest, respiratory failure, major haemorrhage, severe anaphylaxis, or unconsciousness with no response. These patients go directly to the resuscitation bay, where the most senior staff and the most advanced equipment are concentrated.

Category 2 — Very Urgent (Orange)

Target: seen within 10 minutes.

Conditions that are very serious and time-sensitive but where the patient is currently conscious and breathing. Examples include chest pain with suspected heart attack, stroke symptoms within the treatment window, severe breathing difficulty, significant burns, and high-mechanism trauma (such as a car crash at speed).

Category 3 — Urgent (Yellow)

Target: seen within 60 minutes.

The patient has a condition that needs prompt assessment but is not immediately life-threatening. Examples include abdominal pain with abnormal vital signs, moderate bleeding that has been controlled, possible fractures with deformity, high fever with a rash in adults, and acute mental health crisis. This is the most common triage category in a busy department.

Category 4 — Standard (Green)

Target: seen within 120 minutes.

Conditions that need A&E-level assessment but are clinically stable. Examples include simple fractures without deformity, lacerations that need stitching but are not bleeding heavily, abdominal pain with normal vital signs, and stable chronic conditions that have worsened.

Category 5 — Non-urgent (Blue)

Target: seen within 240 minutes.

Conditions that could likely be managed by a GP, pharmacy or UTC. Examples include minor cuts and bruises, long-standing symptoms that have not changed, rashes without systemic symptoms, and medication requests. Patients in this category often wait the longest and may be redirected to a more appropriate service. If you find yourself in category 5, consider whether a UTC or 111 consultation would be faster.

Why arrival order does not equal queue order

In a supermarket, first in line means first served. A&E does not work this way, and for good reason. A patient who arrives at 3 pm with chest pain and abnormal ECG findings will rightly be seen before a patient who arrived at 1 pm with a sprained ankle, even though the ankle patient has been waiting longer.

Within the same triage category, patients are generally seen in arrival order. But when a higher-priority patient arrives, they move ahead of everyone at a lower level. During busy periods, this can mean that category 4 and 5 patients wait for several hours while a steady stream of category 2 and 3 patients are seen first.

This is not queue-jumping. It is the system prioritising based on clinical need. Our guide on practical ways to reduce your wait covers strategies for minimising your time regardless of your triage category.

Can your triage category change?

Yes. If your condition changes while you are waiting — symptoms worsen, new symptoms appear, or you feel significantly worse — tell the triage desk immediately. You can be re-triaged and moved to a higher priority category. Conversely, if a patient's condition stabilises after initial treatment, their effective priority may decrease.

This is why it is important to flag changes. Sitting quietly in the waiting room while your pain escalates does not help you. Walk to the desk, explain what has changed, and ask to be re-assessed.

What affects wait time beyond triage

Even within the same category, several factors influence how quickly you are seen:

• Department workload — how many patients are ahead of you in your category and in higher categories
• Staffing levels — more clinicians means faster throughput, but staffing varies by time of day and day of the week
• Bed availability — if the department is full and patients are waiting for ward beds, new assessments slow down
• Specialist availability — if your condition needs a specialist opinion (orthopaedics, psychiatry, paediatrics), you wait for that team's availability as well as the general queue
• Diagnostic load — if many patients ahead of you need blood tests or imaging, the results queue grows

Our guide on how wait times are measured explains how the published wait-time figures relate to your actual experience.

How to make the most of triage

• Be honest and specific about your symptoms. Do not downplay them to seem brave, and do not exaggerate to try to get seen faster. Both lead to worse outcomes.
• Mention all relevant history. If you have a heart condition and are presenting with chest pain, say so immediately — it changes the risk assessment.
• Bring your medications list. Drug interactions and current treatments directly affect triage decisions.
• Ask your triage category if it is not volunteered. You have the right to know where you stand.
• Bring a companion if possible. A companion can corroborate your account, remind you of details you might forget under stress, and advocate on your behalf if you become too unwell to communicate effectively.

Triage for specific populations

Children

Paediatric triage uses age-adjusted vital sign thresholds. A heart rate of 140 is concerning in an adult but may be normal in a toddler. Triage nurses use age-specific charts, so knowing your child's exact age in months and approximate weight helps them assess accurately. See our children's A&E guide for more.

Older adults

Older patients may present atypically — confusion instead of fever, falls instead of chest pain, drowsiness instead of breathlessness. Experienced triage nurses know this, but if you are accompanying an older adult, explain what has changed from their baseline. "She was fine yesterday and now she can't stand" is powerful triage information. Our elderly A&E guide covers additional considerations.

Mental health presentations

Mental health crises are triaged using the same urgency framework. A patient who has taken an overdose or is actively self-harming is triaged as high priority for physical safety. A patient in severe psychological distress but physically unharmed may be categorised lower, which can feel dismissive but reflects the physical-safety focus of the triage system. Our mental health crisis guide explains what to expect.

Common frustrations and why they happen

"People are going in before me." This is almost always because they are in a higher triage category. It is not queue-jumping.

"I have been here three hours and no one has told me anything." This is a genuine service failure. You have the right to request an update. Approach reception and ask calmly.

"They just put me in category 4 and I am in real pain." Pain alone does not determine triage category — clinical risk does. However, if your pain is escalating or you develop new symptoms, ask to be re-triaged. You can also ask for pain relief while you wait — triage nurses can sometimes administer or request analgesia before you see a doctor.

Bottom line

Triage exists to ensure the sickest patients are seen first, regardless of when they arrived. Understanding this removes frustration and helps you engage constructively with the process. If your condition changes while you wait, speak up. If you are triaged as low priority and face a long wait, consider whether a UTC or alternative service might meet your needs faster. And always check live wait times before choosing which department to visit.