In medical documentation, which part of the HPI contains only subjective data?

The chief complaint is the part of the history of present illness (HPI) that contains only subjective data. It reflects the patient's own words regarding their primary concern or reason for seeking medical attention. This subjective narrative is crucial because it provides insight into the patient's symptoms, feelings, and perceptions regarding their health, which are essential for guiding further evaluation and treatment.

In contrast, past history encompasses previous medical events, surgeries, and conditions, which are usually factual and objective rather than subjective. The physical examination section consists of the healthcare provider's observations and findings, which are also objective measurements of the patient's current health state. Lastly, the assessment and plan involve the clinician's interpretation of the clinical data gathered and the strategies for management, encompassing clinical reasoning rather than patient-reported information.