Overview of inpatient coding.

The main classification-based and nomenclature-based coding systems used in the United States, as well as the process and importance of documenting in the patient record, are discussed. Hospital pharmacists usually have limited knowledge of and exposure to coding and reimbursement in the inpatient system. Coding allows for reporting of mortality data to the World Health Organization (WHO), reporting morbidity data in the U.S., and providing data for reimbursement from third-party payers to hospitals for services provided. Coded information is also the primary source for administrative management of medical services and a source of epidemiologic and statistical data from inpatient stays. In order to better understand inpatient coding and reimbursement, this article will discuss the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) coding system; the Healthcare Common Procedure Coding System (HCPCS); the process and importance of appropriate chart documentation; and the development of the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) coding system. Coding in the inpatient setting enables hospital billing and provides statistical data for epidemiology and financial planning. The ICD-9-CM is a clinically modified version of the international ICD-9 system used for coding both diagnoses and procedures in the United States. Coding is derived from documentation found in the patient's chart. Appropriate documentation is key for quality and continuity of care and compensation for resources utilized. In the future the ICD-9-CM will be replaced by the 10th revision, ICD-10, which is already in use in many countries in Europe.