Intended for healthcare professionals

Observations Ethics Man

ABC of medical confidentiality

BMJ 2020; 368 doi: (Published 04 March 2020) Cite this as: BMJ 2020;368:m857
  1. Daniel Sokol, medical ethicist and barrister
  1. 12 King’s Bench Walk, London
  1. daniel.sokol{at}
    Follow Daniel on Twitter @DanielSokol9

It is right for the bar to be set high for breaching trust

A woman who sued the NHS for not telling her during pregnancy that her father had Huntington’s disease has lost her case.1 The High Court found that doctors who maintained the confidentiality of her father and refused to tell his pregnant daughter, referred to as ABC, about his Huntington’s disease were neither negligent nor in breach of her human rights.2

The father’s genetic condition was diagnosed during the course of his hospital treatment. He refused to allow disclosure to his pregnant daughter. She discovered the diagnosis through an inadvertent “slip” by a psychiatrist some months after the birth of her child and sued three NHS trusts for not disclosing the diagnosis in time for her to obtain an abortion. She claims that she would have chosen to have the termination if she had known that she had a 50% chance of inheriting the gene.

The key feature of the ABC case for lawyers is the establishment of a new duty of care towards certain people at risk who fall outside the doctor-patient relationship. For clinicians, this new legal duty should be of minimal relevance in practice, as it mirrors existing professional guidance.

The case’s significance to frontline doctors is in demonstrating that the court will give them considerable latitude when they balance the pros and cons of non-consensual disclosure of a patient’s confidential information.

Once the court in the ABC case found that the medical team had a duty of care towards the daughter, the question was whether the decision not to disclose the father’s diagnosis was one that no reasonable doctor could have reached. In other words, was breaching confidentiality the only reasonable course of action? The court rightly answered no. Had it done otherwise, it would have eroded dangerously the duty of confidentiality.

The daughter’s lawyers instructed a clinical geneticist with expertise in ethics, Anneke Lucassen. The judge remarked, “At one point in her evidence, Professor Lucassen accepted that the decision was one about which reasonable and responsible clinicians could have taken a different view. Although that was contrary to other parts of her evidence, I do not think she had been confused by the question when she answered as she did.”

This change of position will have dealt a blow to the claimant’s case.

Gwen Adshead, a psychiatric expert also instructed by the claimant, held firm in her view that no responsible psychiatrist would have failed to breach the father’s confidentiality, but the judge found that “she may have underplayed the risk of harm to [the father] and she had not mentioned the public interest in maintaining confidentiality in her report.”

David Craufurd, the geneticist instructed by the NHS, had extensive experience of dealing with families affected by Huntington’s disease. He declared that he would not have breached the father’s confidentiality. The court noted Craufurd’s concerns that “patients are often already reluctant to seek medical help and thought that this could increase if it was known that a diagnosis would be passed on to relatives.”


In my experience, patients whose confidentiality has been violated experience it as a betrayal. They lose faith not only in individual clinicians but in the medical profession as a whole.

The doctor’s duty to keep patients’ secrets is an implicit promise between doctor and patient. Patients are willing to disclose the most embarrassing or personal details to their doctors in reliance on this expectation. By encouraging patients to talk freely about their condition, doctors are better placed to treat patients well. Any step that risks diluting this commitment to confidentiality, which has been built up over centuries, should be taken with great caution.

The court in the ABC case reviewed the guidelines on confidentiality and noted that “non-disclosure is the default position and the bar for breaching confidentiality is relatively high.”

When conducting the balancing exercise, doctors are well advised to acquaint themselves with their professional guidance and seek advice from colleagues and an ethics support service, such as a clinical ethics committee. They should keep a record of the decision making process, the outcome of the deliberation, and what action if any was taken as a result.


  • Competing interests: None declared.

  • Provenance and peer review: Commissioned; not externally peer reviewed.