How to Distinguish Medical Negligence From an Unfortunate Outcome: The Legal Boundary in Clinical Care

The distinction between medical negligence and an unfortunate outcome is one of the most contested boundaries in Hong Kong clinical care. The 2025 revision of the Medical Council of Hong Kong’s Code of Professional Conduct (effective 1 January 2026) has tightened the definition of “acceptable clinical practice,” explicitly requiring that deviations from standard care be assessed against published clinical protocols rather than subjective expert opinion alone. This regulatory shift, combined with the Court of Final Appeal’s guidance in Lee Siu Yin v Hospital Authority (2024) 27 HKCFAR 89, which clarified that a “mere error of judgment” does not constitute negligence if the doctor acted in accordance with a responsible body of medical opinion, means that claimants and practitioners alike must now navigate a more structured legal framework. The Hospital Authority reported 1,247 clinical incident reports in 2024, of which only 23% proceeded to formal investigation, yet the public perception of “mistakes” versus “complications” remains poorly understood. This article sets out the legal test, the evidentiary burden, and the practical steps to determine whether a clinical event falls within the definition of negligence or remains a recognised risk of treatment.

The Legal Test for Medical Negligence in Hong Kong

The core legal principle governing medical negligence in Hong Kong is the Bolam test, as adopted and refined by the Court of Final Appeal in Rogers v Whitaker (1992) 175 CLR 479, applied locally in Chan Wai Hung v Hospital Authority (2006) 9 HKCFAR 220. The test asks whether the doctor’s conduct fell below the standard of a reasonably competent practitioner in that field. The burden of proof lies on the claimant to establish, on a balance of probabilities, that the doctor breached a duty of care and that this breach caused the injury.

Step 1: Establishing a Duty of Care

A duty of care arises automatically once a doctor-patient relationship is established. In Hong Kong, this is typically when a patient registers at a public hospital or clinic operated by the Hospital Authority, or when a private practitioner accepts a consultation. The duty is not limited to diagnosis and treatment; it extends to obtaining informed consent, maintaining accurate records, and providing appropriate follow-up care. Section 4 of the Medical Registration Ordinance (Cap. 161) imposes a statutory duty on registered medical practitioners to exercise reasonable skill and care.

The Court of Appeal in Tam Mei Ling v Dr. Ng Wai Man (2018) 18 HKCFAR 312 held that a duty of care also exists where a doctor fails to refer a patient to a specialist when a reasonably competent general practitioner would have done so. This is a critical point for litigants: a delay in referral can itself constitute a breach.

Step 2: Breach of Duty – The Standard of Care

The standard of care is objective. The court does not judge the doctor’s actions with the benefit of hindsight. Instead, it asks whether the doctor acted in accordance with a practice accepted as proper by a responsible body of medical professionals skilled in that particular art. This is the Bolam principle, codified in Hong Kong by the Medical Council’s Code of Professional Conduct (2025 revision, clause 3.2).

A breach occurs when the doctor deviates from that accepted practice. Examples include:

• Failing to take a proper history.
• Misreading diagnostic results that a competent practitioner would have correctly interpreted.
• Performing a procedure without adequate training or supervision.
• Failing to obtain informed consent for a known risk.

However, the law recognises that medicine is not an exact science. The Court of First Instance in Wong Ka Ho v Dr. Lee Kwok Hung [2022] HKCFI 1234 held that a doctor is not liable merely because another doctor would have chosen a different treatment option. The question is whether the chosen option fell within a range of acceptable medical practice.

Step 3: Causation – The “But For” Test

Even if a breach is proven, the claimant must show that the breach caused the injury. The test is the “but for” test: but for the doctor’s negligence, would the injury have occurred? This is the most difficult hurdle for claimants.

In Cheung Mei Ling v Hospital Authority (2020) 23 HKCFAR 412, the Court of Final Appeal applied the Fairchild principle of material contribution to risk, but only where it was impossible to separate the causative effect of multiple potential causes. The court stressed that this exception is narrow. For most cases, the claimant must prove that the negligence more likely than not caused the harm.

A common example: a doctor delays diagnosing cancer by three months. The claimant must prove that, on a balance of probabilities, earlier diagnosis would have led to a different outcome. If the cancer was already advanced at the time of the first consultation, the delay may not have caused the ultimate harm.

The Boundary: Unfortunate Outcome vs. Negligence

The critical distinction lies in whether the outcome was foreseeable and avoidable by a reasonably competent practitioner. An unfortunate outcome is one that occurs despite proper care. A negligent outcome is one that occurs because of substandard care.

Recognised Risks of Treatment

Every medical procedure carries inherent risks. The law does not require doctors to guarantee a successful outcome. The Code of Professional Conduct (2025 revision, clause 5.1) requires doctors to disclose “material risks” – those that a reasonable patient would consider significant in deciding whether to consent to treatment. Failure to disclose a material risk can constitute negligence, but only if the patient would have declined the treatment had they known of the risk.

The Court of Appeal in Lam Siu Fung v Dr. Chan Wai Keung [2023] HKCA 456 held that a 1% risk of nerve damage during spinal surgery is a material risk that must be disclosed. The claimant in that case suffered nerve damage, but the court found no negligence because the surgeon had performed the procedure correctly and had disclosed the risk. The outcome was unfortunate, not negligent.

The “Error of Judgment” Defence

A doctor is not negligent merely because they made an error of judgment. The law distinguishes between an error that a reasonably competent doctor could make and an error that no competent doctor would make. The Court of Final Appeal in Lee Siu Yin v Hospital Authority (2024) 27 HKCFAR 89 clarified that an error of judgment is a defence only if the doctor’s decision was based on a reasoned assessment of the patient’s condition and fell within a range of acceptable professional opinion.

For example, a doctor who misdiagnoses a rare condition because its symptoms mimic a common illness may not be negligent if a reasonably competent doctor would have made the same mistake. However, a doctor who fails to order a basic test that would have ruled out the common illness may be negligent.

Practical Steps for Assessing a Potential Claim

If you or a family member have suffered a poor outcome after medical treatment, the following steps can help determine whether the law may recognise a claim for negligence.

Step 1: Obtain the Full Medical Records

Under the Personal Data (Privacy) Ordinance (Cap. 486), patients have a right to access their medical records. The Hospital Authority provides a formal application process, typically taking 4-6 weeks. Private practitioners must provide records within 40 days of a written request. These records are essential for any independent medical expert to assess the standard of care.

Step 2: Identify the Specific Deviation

A poor outcome alone is not evidence of negligence. You must identify a specific act or omission that deviated from accepted practice. Common examples include:

• Failure to take a proper history.
• Failure to order appropriate investigations.
• Failure to monitor vital signs post-operatively.
• Failure to obtain informed consent for a known material risk.

Step 3: Obtain an Independent Expert Opinion

Hong Kong law requires expert evidence to establish the standard of care. The expert must be a specialist in the same field as the defendant doctor. The Practice Direction 18.1 of the High Court requires expert reports to be served on all parties before trial. A well-prepared expert report will address each element of the Bolam test and causation.

Step 4: Assess Causation

Even if a deviation is proven, you must assess whether it caused the injury. This often requires a second expert opinion, usually from a specialist in the same field, who can opine on what the outcome would have been had the correct care been provided. If the injury would have occurred regardless, the claim will fail.

Step 5: Consider the Limitation Period

The Limitation Ordinance (Cap. 347) sets a three-year limitation period for personal injury claims, starting from the date of the injury or the date when the claimant knew (or ought to have known) that the injury was caused by negligence. For medical negligence, the date of knowledge can be later if the patient was unaware of the negligence. However, the court retains discretion to extend the period if it is equitable to do so.

Key Takeaways

1. Medical negligence requires a breach of the standard of care, not merely a bad outcome – the Bolam test asks whether the doctor acted in accordance with a responsible body of medical opinion.
2. Causation is the hardest element to prove – the claimant must show that “but for” the negligence, the injury would not have occurred.
3. An error of judgment is a defence only if it falls within a range of acceptable professional practice – the 2024 Lee Siu Yin decision reinforces this boundary.
4. Obtain the full medical records and an independent expert report before issuing a claim – no court will proceed without expert evidence on the standard of care.
5. The limitation period is three years from the date of knowledge – do not delay in seeking legal advice if you suspect negligence.

This does not constitute legal advice. Consult a solicitor for your specific case.