Patients attending Accident and Emergency departments expect rapid clinical assessment and treatment for potentially serious illness or injury. Naturally, however, the speed at which emergency medicine operates can also create circumstances where important warning signs are overlooked.
Clinical negligence within A&E most frequently arises from diagnostic failures during the early stages of assessment. In many cases, the issue is not the quality of treatment itself, but rather the failure to recognise the seriousness of the patient’s condition before discharge.
From a legal perspective, A&E negligence cases focus on whether the treatment provided fell below the standard expected from reasonably competent emergency clinicians. If that failure leads to avoidable harm, the circumstances may form the basis of a clinical negligence claim.
To explore this further, this article will be split into five main sections:
- The diagnostic pathway in A&E
- Common diagnostic errors
- Systemic and human factors contributing to error
- When diagnostic errors qualify as negligence
- The clinical negligence process
How the Diagnostic Pathway Works in A&E
Emergency departments rely on structured clinical pathways to manage large volumes of patients safely.
While the precise procedures may vary between hospitals, most emergency departments follow a four-stage process: check-in, triage, treatment, and outcome. Each stage plays an important role in identifying potentially serious illness or injury.
1. Check-In and Initial Registration
The first stage of the process begins when a patient arrives at the emergency department and registers at reception. Basic details are recorded, including the patient’s personal information, presenting complaint, and any immediate concerns reported on arrival.
Although this stage is primarily administrative, it provides the first opportunity for staff to identify patients who may require urgent attention. Individuals who appear severely unwell may be prioritised immediately for clinical assessment before completing the full registration process.
2. Triage and Initial Clinical Assessment
Following registration, patients are assessed by a triage nurse who evaluates symptoms and relevant medical history to determine the urgency of treatment. The purpose of triage is to prioritise patients according to clinical risk so that those with the most serious conditions are treated first.
Triage decisions are often supported by physiological scoring systems such as the National Early Warning Score (NEWS2) and the Manchester Triage System (MTS). This tool measures indicators including respiratory rate, oxygen saturation, blood pressure, pulse rate, temperature, and level of consciousness. Elevated scores indicate possible deterioration and should prompt escalation to senior clinicians and time-critical pathways (for example, stroke, chest pain, major haemorrhage, or sepsis bundles).
Although triage systems are designed to identify critically unwell patients, they are not diagnostic tools. Their purpose is to prioritise care rather than confirm the underlying condition. As a result, subtle or evolving illnesses may initially appear less urgent and require vigilant assessment.
3. Treatment and Diagnostic Investigation
Once triage is complete, patients are assessed by a doctor or emergency medicine practitioner. The clinician performs a clinical examination and determines whether diagnostic tests are required in order to identify the underlying cause of the patient’s symptoms. Ongoing review is often necessary, as a single set of observations or one test may not be sufficient to exclude serious disease.
Investigations frequently used in A&E include:
- Blood tests to identify infection, organ dysfunction, cardiac injury, clotting abnormalities, or internal bleeding.
- Radiological imaging such as X-rays, CT scans, or MRI scans.
- Electrocardiograms to assess cardiac abnormalities supported by serial troponin testing where indicated.
- Urine or microbiological tests where infection is suspected.
- Point-of-care testing (for example, capillary blood glucose, arterial blood gases, lactate) in acutely unwell patients.
4. Outcome and Discharge Decisions
The final stage of the emergency department pathway involves determining the appropriate outcome for the patient. Depending on the findings of the assessment and investigations, patients may be discharged with advice, referred for specialist review, admitted to hospital for further treatment, or transferred for emergency procedures.
Discharge decisions in particular require careful judgement. Patients who appear stable at the time of assessment may still have conditions that develop or worsen over time. Therefore, clear safety-netting advice and appropriate follow-up arrangements are essential to ensure that emerging complications are recognised promptly.
Effective safety-netting typically includes:
- Specific red-flag symptoms to watch for.
- A realistic timeframe for expected improvement.
- Instructions on how and where to seek urgent reassessment.
- Documentation of any pending or repeat tests (for example, repeat X-rays or blood tests).
Common Diagnostic Errors in A&E
Certain types of diagnostic failure appear repeatedly in emergency department negligence claims. Although the clinical circumstances vary, these cases often involve conditions where early symptoms may appear mild or resemble less serious illnesses.
Common examples below:
Delayed Diagnosis of Sepsis
One of the most serious conditions associated with delayed diagnosis in emergency departments is sepsis. The condition arises when the body’s response to infection triggers widespread inflammation and organ dysfunction.
Early symptoms of sepsis are often non-specific and may include fever, fatigue, confusion, and rapid breathing. These symptoms overlap with many minor illnesses, which can make early recognition difficult.
When sepsis is identified early, clinicians can administer intravenous antibiotics and fluids to stabilise the patient and control the infection. Meanwhile, delayed treatment may potentially lead to septic shock, organ failure, and death.
Missed Fractures
Fractures represent another common source of diagnostic error in A&E settings. Patients frequently attend emergency departments following falls, sporting injuries, or road traffic accidents.
Some of these injuries can be difficult to detect on initial examination or imaging.
Scaphoid Fractures
The scaphoid bone in the wrist is particularly vulnerable to missed diagnosis. Fractures of this bone often occur when a person falls onto an outstretched hand. Early X-rays may appear normal even when a fracture is present.
Because the scaphoid has a limited blood supply, untreated fractures can lead to complications such as bone necrosis and long-term wrist instability. National guidance therefore recommends immobilisation and repeat imaging when clinical suspicion remains high.
Hip Fractures in Older Patients
Hip fractures are another injury that may be overlooked, particularly in elderly patients with osteoporosis. The fracture line can be difficult to visualise on standard X-rays (especially if degenerative bone changes are present).
Delayed diagnosis may prevent timely surgical intervention and significantly increase the risk of long-term complications.
Misdiagnosed Heart Attacks
Cardiac emergencies also present a significant diagnostic challenge in emergency departments. Patients experiencing a heart attack do not always present with the classic symptom of severe chest pain. Instead, symptoms may include shortness of breath, nausea, fatigue, syncope or discomfort in the jaw, neck, or arm.
Because these symptoms can resemble less serious conditions – such as indigestion or anxiety – the underlying cardiac problem may not immediately be recognised.
Diagnosis typically relies on a combination of clinical assessment, electrocardiograms (ECG), and blood tests that measure cardiac enzymes such as troponin, usually with serial sampling. If these investigations are not performed or interpreted correctly, the heart attack may be missed during the initial attendance.
Delayed diagnosis or misdiagnosis can significantly increase the risk of permanent heart damage or fatal complications.
Failure to Diagnose Stroke
A stroke occurs when blood flow to part of the brain is interrupted, either due to a blockage (ischaemic stroke) or bleeding within the brain (haemorrhagic stroke). Without rapid treatment, brain cells begin to die within minutes.
Public awareness campaigns often focus on the FAST test, which highlights common stroke symptoms, including facial drooping, arm weakness, and speech difficulties. However, not all strokes present with these classic signs.
When symptoms are atypical or develop gradually, the possibility of stroke may not immediately be recognised. This can lead to delays in diagnostic imaging – such as CT brain scans or MRI scans – which are essential for confirming the diagnosis and determining the appropriate treatment.
For many patients with ischaemic stroke, treatments such as thrombolysis or mechanical thrombectomy are only effective within a limited time window. If diagnosis is delayed, patients may lose the opportunity to receive these interventions, increasing the likelihood of permanent neurological damage.
Additional Resource: A Guide to Misdiagnosed Strokes and Heart Conditions in A&E
Pulmonary Embolism
Pulmonary Embolism can present with pleuritic chest pain, shortness of breath, tachycardia, haemoptysis, or syncope, but may also be subtle. Failure to apply validated risk tools (such as Wells score), omit D-dimer testing or CT pulmonary angiography when indicated, or misinterpret ECG and chest X-ray findings can lead to missed or delayed diagnosis.
Aortic Dissection
Aortic dissection is a time-critical emergency that may mimic musculoskeletal pain, myocardial infarction, or stroke. Classic tearing chest or back pain may be absent. Failure to consider the diagnosis in hypertensive patients, those with connective tissue disorders, or with pulse deficits can delay CT aortography and definitive management.
Failure to Diagnose a Brain Tumour
Brain tumours may initially present with non-specific symptoms such as persistent headaches, seizures, visual disturbances, or changes in cognition. Where appropriate investigations or referrals are unreasonably delayed, patients may lose the opportunity for earlier treatment. In some cases, patients may have grounds to bring a claim relating to a brain tumour.
Subarachnoid Haemorrhage (SAH)
Patients may present with a sudden severe “thunderclap” headache, neck stiffness, photophobia, or transient loss of consciousness. Misattribution to migraine or tension headache without appropriate imaging (CT head within the recommended window and, if negative with ongoing suspicion, lumbar puncture) is a common source of error.
Cauda Equina Syndrome
Cauda equina typically presents with severe back pain, bilateral sciatica, saddle anaesthesia, bladder or bowel dysfunction, and lower limb weakness. Failure to recognise red flags and obtain urgent MRI, or delay in referring for neurosurgical assessment, can cause irreversible neurological injury.
Additional resource: A Guide to Cauda Equina Syndrome
Ectopic Pregnancy
In early pregnancy, abdominal pain and bleeding may be misattributed to miscarriage or gastrointestinal illness; failure to check pregnancy status or arrange timely ultrasound can delay diagnosis of ectopic pregnancy.
Testicular Torsion
In males with acute scrotal pain, failure to consider and urgently act on suspected testicular torsion (time-critical surgical exploration) can result in loss of the testis.
When Errors Become Clinical Negligence
Importantly, not every diagnostic error in an emergency department amounts to clinical negligence. For a legal claim to succeed, four key elements must generally be established
These legal principles determine whether the care provided by a healthcare professional fell below an acceptable standard and whether that failure caused harm.
1. Duty of Care
The first requirement is establishing that a duty of care existed. In an A&E setting, this is usually straightforward. When a patient attends hospital for treatment, the healthcare professionals responsible for their care have a legal obligation to act in the patient’s best interests and provide treatment that meets accepted medical standards.
2. Breach of Duty
A breach of duty occurs when the care provided falls below the standard expected of a reasonably competent healthcare professional in the same circumstances. Under the Bolam/Bolitho principles, the Court considers whether the clinician’s actions were supported by a responsible body of medical opinion and whether that opinion is logically defensible.
In emergency departments, for instance, this may involve failing to recognise serious symptoms and discharging them without adequate assessment, omitting appropriate investigations, not escalating to senior review, or discharging a patient without adequate assessment or safety-netting.
3. Causation
It must also be shown that the breach of duty directly caused the harm suffered by the patient. This means demonstrating that, had the correct diagnosis or treatment been provided at the appropriate time, the outcome would likely have been significantly better.
This generally requires demonstrating that, on the balance of probabilities, earlier diagnosis or correct treatment would have led to a materially better outcome. In some cases involving cumulative causes, the material contribution test may be relevant.
4. Damage
Finally, the claimant must have suffered measurable harm as a result of the negligent care. This harm may be physical, such as permanent injury or deterioration of a medical condition. It may also include psychological trauma, financial losses, or the need for ongoing medical treatment.
Additional losses may include loss of earnings, care and assistance needs, equipment and travel costs, and rehabilitation expenses.
Systemic and Human Factors Contributing to Error
Diagnostic error is not always attributable to a single decision. System-level and human factors frequently contribute, including:
- Overcrowding, corridor care, and delayed access to imaging or specialist review.
- Incomplete or infrequent observations, or failure to act on deteriorating NEWS2 scores.
- Cognitive biases (anchoring, confirmation bias, premature closure) during rapid decision-making.
- Communication failures at handover or between specialties, including inadequate documentation.
- Inadequate safety-netting or poor discharge instructions.
- Barriers to effective assessment, such as lack of interpreters or failure to consider safeguarding or capacity issues.
While context is relevant, resource constraints alone do not excuse substandard care. The Court assesses the reasonableness of clinical decisions in the circumstances faced at the time.
The Clinical Negligence Process
Time Limitations
Most clinical negligence claims in England and Wales must be issued within three years of the date of injury or the date of knowledge of a potential claim. For children, the three-year period runs from their 18th birthday. There is no limitation period while a person lacks mental capacity. Different rules may apply to fatal claims and inquests.
Before Court proceedings, the Pre-Action Protocol for the Resolution of Clinical Disputes encourages early exchange of information. Typical steps include obtaining medical records, obtaining independent expert evidence, sending a Letter of Notification or Letter of Claim, and considering any Letter of Response and offers to resolve the claim. Alternative dispute resolution may be appropriate in some cases.
Evidence and Documentation That Commonly Determine a Claim
In A&E diagnostic cases, contemporaneous records are critical. Key evidence typically includes:
- Triage documentation, observation charts, and early warning scores over time.
- Clinician notes of history, examination findings, differential diagnosis, and safety-netting advice.
- ECG strips and reports; laboratory results and timestamps; imaging and radiology reports.
- Pathway adherence records (for example, sepsis bundles, stroke and chest pain pathways) and escalation to senior review.
- Discharge summaries, patient information leaflets provided, and follow-up or recall arrangements.
- Hospital incident reports, complaint responses, and any internal investigation findings.
Compensation and Outcomes
If liability and causation are established, damages aim to place the claimant, so far as money can, in the position they would have been in absent the negligence. Heads of loss often include: general damages for pain, suffering and loss of amenity, assessed with reference to the Judicial College Guidelines.
Special damages for past and future financial losses, including earnings, medical expenses, therapy, equipment, travel, and care. In fatal cases, claims may include dependency losses and awards under relevant legislation, together with funeral expenses.
Making an A&E Negligence Claim
If you suffered harm because a serious condition was missed or treatment was delayed in A&E, you may be able to pursue a clinical negligence claim.
This guide provides general information only and does not constitute legal advice. The next steps commonly involve requesting your medical records, preparing a detailed timeline of events, and obtaining independent expert opinions on breach of duty and causation.
To discuss a potential claim, contact our team of specialist solicitors.