The history of a patient's disease can be reported as a second code for ICD-10-CM, and it can be found in which chapter?

The correct choice relates to Chapter 21 of the ICD-10-CM coding system, which includes codes ranging from Z00 to Z99. In this chapter, codes are specifically designated for factors influencing health status and contact with health services, including personal and family history of diseases. This allows coders to accurately represent the patient's history of diseases when it is relevant for the current visit or treatment.

For coding purposes, including the history of a patient's disease provides additional context and can influence treatment decisions, risk assessments, and preventive measures. Therefore, when encountering a patient's historical medical information that is significant for the current episode of care, coders use this chapter to appropriately document and communicate such details to healthcare providers and payers, enhancing the overall understanding of the patient's health.

Other chapters focus on different aspects of medical classification. For example, specific chapters may cover particular disease categories or body systems, but Chapter 21 is uniquely tailored to capture the nuances of health history, making it the most appropriate choice for reporting a patient's disease history.