What must each ICD-10-CM code assigned be supported by?

Each ICD-10-CM code assigned must be supported by documentation linked to that claim. This documentation serves as evidence for the diagnosis and provides justification for the medical services rendered. Accurate and thorough documentation is essential in ensuring that the coding reflects the patient's clinical picture and supports the medical necessity of the treatment provided.

In the context of coding, this means that the information in the patient's medical record should clearly correlate with the ICD-10-CM codes reported to ensure compliance with regulations and to avoid potential denials or audits. Each diagnosis should be substantiated by the physician's notes, medical history, and any relevant test results or clinical findings present in the documentation, as they affirm the appropriateness of the codes assigned.

The other answer choices do not fulfill the requirement for supporting ICD-10-CM codes. General assumptions regarding an illness lack specificity and are not acceptable for coding purposes. While patient history can provide context, it must correlate with detailed documentation to be valid. Although physician preferences may influence coding practices, they cannot replace the need for documented evidence linking the specific diagnosis to the provided care. Therefore, proper documentation is the essential foundation for accurate coding.