Nursing care
Implied vs express consent: actions, spoken and written agreement, and emergencies
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated October 2026
Short answer
Express consent is stated directly, either spoken or written, as with a signed form before surgery. Implied consent is inferred from the patient's actions, such as holding out an arm for a blood pressure reading. In emergencies, consent may be presumed when a patient cannot decide and delay would cause harm. Any form can be withdrawn by a capable patient.
Ask how the patient showed agreement
Implied consent is agreement shown by behaviour in a situation where the request is clear and the procedure is routine and low risk. A patient who rolls up a sleeve when the nurse explains a blood glucose check, or opens their mouth for a thermometer, is communicating consent without saying yes. The nurse still explains what they are about to do.
Express consent is stated, either verbally or in writing. Verbal express consent suits many bedside procedures, such as inserting a peripheral IV after explanation. Written consent is used for major or higher-risk interventions such as surgery, anaesthesia, blood transfusion in many organisations and research, and records that the informed consent discussion took place.
Separate informed consent from the nurse's witnessing role
For procedures that need informed consent, the person performing the procedure explains the diagnosis, purpose, risks, benefits and alternatives, including declining. The nurse's role is commonly to witness the signature, confirm the patient appears to understand and is acting voluntarily, and check that the form is complete. Signing as witness does not mean the nurse gave the explanation.
If the patient has questions about risks or seems unsure, the nurse pauses and contacts the provider rather than answering beyond scope or proceeding. Capacity matters: a patient who is heavily sedated, intoxicated or delirious may not be able to give valid consent. Refusal alone does not prove incapacity; a capable adult may decline even beneficial treatment.
Emergencies, withdrawal and the limits of implied consent
When a patient lacks capacity, no surrogate is available and delay would seriously harm them, treatment may begin under the emergency exception, sometimes called presumed consent. The patient or surrogate is informed as soon as possible and consent is sought for ongoing care. A known prior refusal, such as a valid advance directive, still applies in an emergency.
Implied consent is narrow. Arriving at the hospital does not imply agreement to every test or procedure. A patient who pulls away, says no, or appears frightened is withdrawing consent, and the nurse stops and clarifies. Continuing after refusal can amount to battery. Document refusals, the explanation given and notification of the provider.
Special situations: minors, interpreters and sedation
For minors, a parent or legal guardian usually gives consent, although laws in many places allow certain young people to consent to specific services, such as sexual health care, and emancipated minors may consent for themselves. The nurse checks local policy rather than assuming. Explaining the procedure to the child at an appropriate level and seeking their agreement remains good practice.
Consent must be understood to be valid. Use a qualified medical interpreter for patients with limited English rather than relatives, and confirm understanding with teach-back. Do not obtain or witness consent after sedating medicines have impaired judgement. If a patient's capacity seems doubtful, notify the provider, who assesses capacity and, if needed, involves the legal surrogate.
Work through an original scenario
Hypothetical item: a nurse explains that she needs to check a patient's blood pressure, and the patient extends his arm. Later he signs a surgical consent form, then asks the nurse what the chance of nerve damage is. Which response is best? Options: answer from her own knowledge, tell him the form is signed so it is too late, notify the surgeon, or reassure him that problems are rare.
Notifying the surgeon is best because informed consent requires the person doing the procedure to address risk questions. The extended arm illustrates implied consent; the signature shows written express consent. Telling him it is too late is wrong because consent can be withdrawn, and offering reassurance or risk figures goes beyond the nurse's role.
Sources and further reading
AMA Code of Medical Ethics: Informed consent. Capacity assessment, information to disclose, documentation, and the emergency exception with later informing of patient or surrogate.
MSD Manual Consumer Version: Informed consent. Signed documents for major treatment, presumed consent in emergencies unless previously refused, surrogates, and refusal not proving incapacity.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our safe and effective care practice questions are the closest set to what this page covers.
One question from the safe and effective care set
A nurse on a medical unit receives report on four clients. Which client should the nurse assess first?
Rationale
Prioritization items are airway, breathing, circulation, in that order — the ranking survives every rewording. Audible gurgling around a fresh tracheostomy is a partially obstructed airway and it is the only option that can kill the client in the next few minutes. Fever, post-op pain, and a glucose of 232 are all real problems that need the nurse, just not first.
Answer: C
Common questions
Is verbal consent legally valid?
Verbal express consent is valid for many procedures. Organisational policy and law decide which interventions require written consent, typically surgery and other higher-risk treatments.
Can a patient withdraw consent after signing the form?
Yes. A capable patient can withdraw consent at any time. The nurse stops preparations, notifies the provider and documents the patient's decision.
Who obtains informed consent for surgery?
The surgeon or person performing the procedure. The nurse commonly witnesses the signature and checks understanding and voluntariness, escalating any doubts.
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