The International Categorization of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) is a classification and coding system used in the United States to classify and code diagnoses, signs and symptoms, and procedures associated with hospital care. The system is significant because it provides more detailed diagnostic and morbidity classification information. The method is based on international illness classifications, normally published by the World Health Organization, and it employs specific codes that allow clinicians to identify diseases during diagnosis. It is critical to comprehend the system's format to comprehend how the system can be interpreted. As a result, there are three key components of this system's format to comprehend: it makes references to an alphabetic index, a tabular, and chapters.

The alphabetic index is separated into three areas in the ICD-10-CODING MANUAL: the index to diseases and injuries, the table of chemicals and medications, and the external cause of injuries index. This index is frequently used in outpatient settings to discover the etiology of a patient's symptoms as well as to diagnose them. The index also includes three minimum levels of indentation, which are necessary for identifying the main terms, subterms, and carryover lines. The codes identified are then located in the tabular once the alphabetic index is accessed. Because the coder must validate the number with the tabular, one cannot code directly from the alphabetic index. The tabular essentially consists of a series of codes used to describe the alphabetic index. Finally, the chapter is regarded as the system's primary division. The chapter includes a section representing a collection of linked conditions, a category representing a specific disease, a subcategory that provides more specific data about the category's features, and a subclassification that provides even more specific details about the conditions (Buck, 2016).