consentimiento informado

What is Informed Consent?


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Informed Consent is a process by which a patient voluntarily confirms his/her decision to participate in a given trial after having been duly informed of all aspects of the trial that are relevant to his or her decision to participate. Informed Consent is documented by means of the corresponding written, signed and dated document. 

First, the patient is duly informed of the trial objectives, diagnostic and therapeutic procedures, health benefits and risks, etc., by the healthcare professionals. Then, he or she will have the necessary capacity to freely and voluntarily make a decision whether to enroll in the trial. 

In order to obtain a patient’s consent, the physician must submit all information related to the clinical trial in a language that is easy to understand. All questions the patient has about the trial must be answered before he or she signs the document. 

Types of Informed Consent  

The Informed Consent for research or participation in a clinical trial, according to Ley 41/2002, de 14 de noviembre, donde se regula el derecho del paciente y su autonomía [the Patient Autonomy Act], must always be in writing. It is made up of two parts: 

  • Patient Information Sheet (PIS), which contains all the relevant information about the clinical trial written in clear and comprehensible terms. 
  • Informed Consent Form (ICF): the page to be signed by the patient and doctor. Once signed, this form becomes legally binding. 

There may be other types of consent in the Informed Consent Form: 

  • Informed Consent for minors: when the minor is under 12 years of age, his or her legal representative will sign the informed consent. Between the ages of 12 and 16, consent must be given by the legal representative(s), but the opinion of the minor is also required. From 16 years of age onwards, the minor is autonomous for decision-making without involving another person, except in situations of serious risk to the health of the patient, where legal representatives are required. 
  • Informed Consent by representation: in this case, a third person will provide the consent. However, provided the conditions allow, the patient must give his/her consent after receiving the information adapted to his/her level of understanding. Current legislation recognizes two specific circumstances: 
  • When the treating physician deems that the patient is not capable of making decisions, or if the patient’s physical and mental health does not allow him or her to make that type of decision. 
  • When the patient’s decision-making capacity has been legally determined to be altered. 
  • Informed Consent Form for biological samples: this consent will be used if biological samples (blood, urine, biopsies, etc.) are going to be collected or transferred during the trial. This type of consent details the objectives of the collection and/or transfer of the samples, the methods used, the patient’s rights regarding the information generated from his or her samples, etc. 

Importance of Informed Consent in clinical trials  

The importance of Informed Consent is based on three main pillars to protect the autonomy of the patient, to safeguard their rights and to ensure their health. 

When a patient is sufficiently informed and knows and understands all aspects relevant to his/her participation in a trial, he/she is able to make the most appropriate decision. The principle of autonomy is based on the fact that the patient is the best judge of his or her health when he or she has been appropriately informed and acts freely. 

As this is a binding legal document, the patient’s rights are guaranteed. The patient has the right to be informed of any relevant changes occurring during the conduct of the trial that could pose a risk to his or her health. In this case, the patient will have to sign a new consent form accepting those changes. 

All patient data must be protected at all times without violating his or her confidentiality. The patient also has the right to know what alternative procedures or treatments are available outside of the trial. 

If the patient decides not to participate in the trial or wishes to withdraw from it during the trial, this decision will have no negative effect on his or her healthcare, either now or in the future. That is, there will be no penalty or loss of medical benefits to which the patients are otherwise entitled

The principle of beneficence is a concept in research ethics that states that the investigators’ objective must be the wellbeing of the participants in the clinical trial or medical research. The health of the patient is ensured through compliance with this principle and the requirement of review and acceptance by a Research Ethics Committee both to conduct the clinical trial and to validate the informed consent. 

What is the correct process for signing the Informed Consent?  

It’s not just a matter of signing. First, patients have to be informed on the different aspects and follow a process for the decision-making to be valid. First, the doctor must inform the patients of all aspects relevant to them regarding their participation in the trial. 

The patients will be given a copy of the Informed Consent and enough time to think about their participation or to consult with whoever they consider necessary (family, friends, etc.). The doctor must answer any questions they have. 

If after this point the patient decides to participate, he or she must write his or her name and sign and date the document. The doctor must also write his or her name, and sign and date in the same way. 

When the consent is correctly signed by both parties, the same is done on another identical consent for the same study. One copy will be kept by the hospital for filing together with the patient documents, and the other copy will be kept by the patient. Patients should keep their copy throughout the entire course of the clinical trial

Finally, the entire process, step by step, is recorded in the patient’s clinical history. 


To summarize

  • What is Informed Consent? It is a process by which the patient freely confirms his or her participation in a clinical trial after being duly informed by the responsible healthcare personnel. 

  • What is the purpose of the Informed Consent? To protect the autonomy of the patient, to safeguard patient rights and to ensure his or her health. 

  • How is an Informed Consent Form written? It is written clearly and simply, so it can be understood by the largest possible number of people. It must explain aspects relevant to the patient’s participation. It must be approved by an independent Ethics Committee. 

  • Who signs the Informed Consent? The patient wishing to enroll (or the responsible person(s), if necessary) and the physician who informed the patient. 

The Informed Consent marks the start of a person’s participation in a clinical trial. Check to see if you can enroll in a cancer clinical trial using our MatchTrial app. 


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