Q&A: Mental incompetency

Q: I believe there was a Coding Clinic several years ago where the diagnosis of “mental incompetence” was changed to “intellectual disability,” but I can’t seem to locate it. What ICD-10 code should be used if a person is documented as “mentally incompetent”?

A: Generally, mental incompetence is a legal concept. The capacity to make medical decisions is a legal framework that should be supported by documentation of the medical or psychiatric condition that is causing the incapacity; it is not a static concept and often shifts.

Depending on state laws, there may be legal filings necessary to justify certain actions. A patient’s right to self-determination outweighs what medical providers may believe is best for them. Because it’s a legal conundrum, it has to be looked at on a case-by-case basis.

The important thing for inpatient documentation is the patient’s diagnosis, not their capacity to make medical decisions. For outpatient treatment, the evaluation and management level might be more complicated as a result of the need for communication with a guardian or other family members.

For coding, code to the etiology of the patient’s condition. This may be intellectual disability, cognitive impairment, or psychiatric disorder. You may want to also consider assigning code Z01.-, Encounter for special examination without complaint, suspected, or reported diagnosis, or Z04.6, Encounter for general psychiatric examination, requested by authority, if appropriate.

Editor’s note: This question and answer were adapted from a thread on the ACDIS Forum. To learn more about participating on the Forum, click here.