01Principles and purposeThe professional or clinical skill and the decisions it supports.
Capacity is a functional ability, not a global label attached to a person. Someone may choose what to eat while being unable to weigh the implications of a major operation, or may understand an operation after pain and hearing difficulties are addressed. Describe the decision precisely: whether to undergo a proposed operation now, whether to accept blood, or whether to agree to an examination. This prevents a broad statement such as lacks capacity from being reused for unrelated choices. The assessment should identify what the person can do with relevant information and what support changes that ability.
The four practical abilities are understanding relevant information, retaining it long enough to decide, using or weighing it, and communicating a choice by any reliable means. In England and Wales the Mental Capacity Act framework also requires the inability to be because of an impairment or disturbance of mind or brain. A communication barrier alone is not that causal impairment. Explain essential information proportionately: the nature and purpose of treatment, realistic options, likely consequences of accepting or declining, and important uncertainties. Testing recall of medical vocabulary is a poor substitute for exploring a decision.
UK jurisdictions have distinct legal frameworks. England and Wales use the Mental Capacity Act 2005; Scotland uses the Adults with Incapacity framework, including relevant certification requirements; Northern Ireland has its own statutory and common-law arrangements whose application must be checked. GMC guidance describes an overall-benefit approach consistent with these frameworks, but one nation’s form or terminology must not be exported automatically to another. When treatment, restraint or a dispute raises legal complexity, involve the responsible senior clinician and appropriate legal support early.
Key points
- Presume capacity and assess the particular decision at the time it must be made.
- Provide communication support and address reversible barriers before concluding that the patient cannot decide.
- An unwise refusal, a diagnosis of dementia or an inability to speak does not establish incapacity.
- Where capacity is absent, check prior wishes, any binding refusal and the scope of another person’s legal authority.
- Relatives contribute knowledge of the patient but are not automatically authorised to consent for an adult.
- In an immediate emergency, provide necessary treatment within lawful limits and document why delay was unsafe.
02Situations and prioritiesThe context, relevant information and actions that matter most.
A patient who understood the operation yesterday may be unable to weigh information during delirium today. Look for a change from baseline and reversible causes such as hypoxia, infection, pain or metabolic disturbance. The urgency of the surgical problem determines how long reassessment can safely wait.
A refusal may reflect fear of dependency, a prior experience or a religious commitment rather than impaired decision-making. Ask the person to explain the likely consequences and their reasons. The assessment concerns their ability to decide, not whether their reasoning produces the clinician’s preferred answer.
Family members may know what the patient would want, but next-of-kin status alone does not confer authority to authorise surgery. Clarify whether there is a legally recognised representative, what powers they hold and whether those powers cover this decision in the current circumstances.
An unconscious patient with immediately life-threatening surgical disease may need treatment before a full meeting is possible. Search for readily available evidence of wishes and lawful restrictions without causing dangerous delay, obtain senior involvement, and provide only what is justified by the emergency and the patient’s interests.
03Assessment and interpretationHow to gather information, assess the situation and recognise uncertainty.
Consider the information, its meaning and its limitations before deciding what follows.
- 01
Define the decision and available time - Why
- Identify what needs deciding and the clinical consequence of waiting.
- Interpretation and limitations
- Urgent does not always mean immediate. A short delay for an interpreter, hearing aids, analgesia or resuscitation may enable the patient’s own decision. Conversely, postponing source control or haemorrhage treatment for an administrative process may worsen the outcome.
- 02
Support information processing - Why
- Remove avoidable obstacles to participation before assessing the functional abilities.
- Interpretation and limitations
- Choose a quieter setting, use plain language and manageable information, and involve communication specialists where helpful. Record the support provided. Repeatedly giving the same complex explanation more loudly does not demonstrate that the patient cannot understand a simpler one.
- 03
Examine understanding and weighing - Why
- Ask the patient to describe the choice and compare its consequences in their own words.
- Interpretation and limitations
- A person may repeat an explanation accurately yet be unable to apply it to themselves because of an impairment. Explore that distinction carefully. Document examples of answers that demonstrate or fail to demonstrate the relevant ability, not merely a screening score.
- 04
Establish wishes and lawful authority - Why
- Review prior decisions and identify who can contribute or decide.
- Interpretation and limitations
- Check relevant records, valid and applicable advance refusals, and the scope of any attorney or other authorised representative. Distinguish evidence about the patient’s values from legal authority to decide. If requirements or validity are uncertain, obtain senior legal advice proportionate to urgency.
04Worked approachesCases with ordered reasoning, an action and a check of the outcome.
01Worked caseDelirium before an urgent operationAn 81-year-old with bowel obstruction needs a decision about surgery within hours. They are intermittently inattentive, have not received their hearing aids and repeatedly say that surgery is a train journey. Their daughter asks to sign the consent form.+
- 1First separate clinical urgency from the capacity question. Ask the senior surgeon how long assessment and treatment of reversible factors can safely take. Continue resuscitation and assessment of the obstruction while arranging hearing support, rather than allowing either task to obscure the other.
- 2Explain the operation and alternatives using short phrases in a quieter setting with the hearing aids available. Ask the patient to describe the problem and what could happen with or without treatment. Their response after support matters more than the initial confused exchange.
- 3If delirium still prevents understanding or weighing the surgical decision, record the impairment, the specific functional difficulty and the time of assessment. Do not conclude that they cannot make every decision, and do not interpret their daughter’s willingness as legal authority.
- 4Check for an applicable advance refusal and any legally authorised representative. Ask the daughter about the patient’s usual independence, values and expressed preferences. The responsible team uses that information alongside benefits, burdens and alternatives within the applicable jurisdictional framework.
- 5Agree and document the justified action, its scope, senior involvement and why further delay would or would not be safe. If necessary surgery proceeds on the appropriate lawful basis, continue involving the patient as far as possible and minimise restriction.
- 6When the acute illness improves, reassess capacity for ongoing choices and explain what was done and why. Ask whether the care plan reflects the patient’s own priorities now that they can participate; recovery of capacity changes who makes subsequent decisions.
02Supported refusalAn informed choice that differs from adviceA patient with capacity declines a recommended amputation after explaining the risk of progressive infection and death.+
- 1Explore whether the refusal reflects an untreated symptom, missing information, pressure or misunderstanding. Offer senior discussion and reasonable alternatives without repeatedly demanding agreement as evidence of understanding.
- 2If the patient can understand, retain, weigh and communicate the choice, respect the decision even when its consequences are grave. A clinician’s distress about the likely outcome does not create permission to operate.
- 3Document the assessment and decision, agree symptom treatment and further support, and explain when and how the patient can reconsider. Continuing care should not become conditional on accepting the proposed operation.
03Immediate emergencyTreatment before a full discussion is possibleAn unidentified unconscious adult arrives with major internal bleeding and needs immediate operative haemorrhage control.+
- 1Activate the appropriate emergency response and obtain senior surgical and anaesthetic leadership. Check information immediately available for relevant refusal or identity while resuscitation proceeds.
- 2If wishes cannot be established and the patient lacks capacity, provide treatment immediately necessary to preserve life or prevent serious deterioration within the relevant law. Choose the option that preserves future choices where clinically feasible.
- 3Record the threat, the inability to consent, the information available and the necessity of the action. Review the basis for further treatment once the emergency has passed or new evidence of wishes becomes available.
05Feedback, follow-up and evidenceReview outcomes, seek feedback and identify what to improve.
- Document the particular decision, relevant information provided, communication support, functional findings and the relationship between impairment and inability where the legal test requires it.
- Reassess when physiology, medication, pain or communication changes. A capacity entry from the previous shift should not substitute for a fresh assessment when the patient’s ability appears different.
- For treatment without the patient’s consent, record the applicable authority, consultations, prior wishes considered, benefits and burdens, and the reason the chosen option was proportionate.
- Explain care to the patient once they can understand, invite questions and seek consent for subsequent decisions. Review any restrictions separately and remove them when no longer necessary.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Screening scores and decision-making
A cognitive screening score may identify impairment but cannot by itself settle capacity for surgery. A low score can coexist with an ability to make a simple supported choice; a normal score can coexist with a specific inability to weigh a particular treatment decision.
A dispute about overall benefit
Use senior review, an independent opinion, advocacy or a case meeting to clarify the disagreement and the patient’s values. Persistent disagreement about significant treatment may require legal advice or court involvement. Record what is urgent and what can safely await resolution.
Restriction requires its own justification
A decision that treatment offers benefit does not automatically authorise any restraint or deprivation of liberty needed to deliver it. Consider necessity, proportionality and separate legal safeguards, and use the least restrictive feasible approach.
Capacity after sedation
Planned sedation can remove the opportunity to revisit a decision. Resolve foreseeable choices and limits beforehand. A newly discovered non-urgent issue during anaesthesia does not become an emergency merely because discussing it later would require another procedure.
07Common pitfallsFrequent interpretation and management errors.
- 01
Calling a patient incapable because they decline the operation the surgical team believes would help.
- 02
Using next of kin as a synonym for a legally authorised healthcare decision-maker.
- 03
Waiting for a specialist capacity assessment when a competent treating clinician can assess the decision and delay would be harmful.
- 04
Assuming that an emergency permits every useful additional procedure instead of limiting action to what the circumstances justify.