In the outpatient setting, which of the following guidelines depicts the reason for the encounter/visit...

In outpatient and physician-office reporting, the diagnosis that best describes the main reason for the visit is reported as thefirst-listed diagnosis. Outpatient coding guidance emphasizes that the “principal diagnosis” concept is primarily an inpatient construct (the condition established after study to be chiefly responsible for admission). In ambulatory encounters, patients are often seen for evaluation, management, follow-up, or symptom assessment, so the coding framework usesfirst-listedto identify the condition, problem, or symptom chiefly responsible for the services provided during that encounter. Co-existing conditions may also be reported when they are addressed or affect care (e.g., monitored, evaluated, assessed/managed, or treated), but they do not replace the requirement to sequence the primary reason for the visit first. Differential diagnoses are not used as the “reason chiefly responsible” in outpatient coding unless a confirmed diagnosis is established; if uncertainty remains, symptoms may be reported instead. Therefore, “first-listed diagnosis” is the correct term for the outpatient setting.