How does a medical error differ from an adverse event?

A medical error is any unintended act (either of omission or commission) or one that does not achieve its intended outcomes [1]:

- The event or circumstance leading to an unintended or undesirable outcome

- The undesirable outcome itself

- An act that is inadvertently at odds with standards or expectations

- An incident

It is important to note that not all medical errors result in harm to the patient. In contrast, an adverse event represents a negative outcome to a patient from healthcare management rather than an error in the management

[2]:

- Any unintended physical injury resulting in disability, impairment, disease, pain, suffering, discomfort, psychological harm, or death for which provision of health care services is a contributing factor.

- An incident during medical treatment that leads to unintended harm or injury to a patient, but which is unrelated to the natural history or progression of the patient’s illness or underlying medical condition.

An adverse event can also be described as any unintended injury or complication resulting in disability, discomfort, prolongation of hospitalization, or death for which medical management (including omission) rather than the patient's underlying condition is a contributing factor.

In other words, a medical error is any deviation from the standard of care, while an adverse event is any harm that results from medical care, whether or not it was due to an error.

References:

1. James JT. A new, evidence-based definition of medical error. Qual Saf Health Care. 2013 Aug;22(8):698-700. doi: 10.1136/qshc.2012.001317. PMID: 23543389; PMCID: PMC3743333.

2. Adverse event. Medical Definition of adverse event. (2022, November 20). MedicineNet. Retrieved November 25, 2022, from https://www.medicinenet.com/adverse_event/definition.htm