A capacity assessment basically determines the validity of a patient's decision to undergo or forgo a particular proposed treatment.

The investigation of the understanding of the patient of the following themes can serve as a guide for presenting him/her information about the medical condition and proposed treatment interventions.
- His / her medical condition
- The natural course of his / her medical condition
- The proposed treatment intervention
- The risks and potential benefits
- The consequences of treatment or intervention refusal
- The alternative treatments

Decisional capacity is dynamic. Patients may alter their decisions, from accepting or refusing treatment to changing decisions between available treatment options. Their capacity to make informed medical decisions can vary as their status changes cognitively, emotionally, and/or physically and as the proposed treatment interventions change.

Adapted from Briggs M et al. A handbook of healthcare ethics and institutional ethics for staff in healthcare institutions. Edmonton. The Bioethics Centre. 1994. Internet. Accessed on October 24, 2018.>