The Evolution of Medical Coding

Originally Reserved for the Dead

Started in the 1600s, Great Britain implemented the practice of the London Bills of Mortality, a medical coding system that assigned a number to a cadaver to describe the cause of death. The objective was to detect the onset of plague epidemics. The International Statistic Institute standardized the approach in 1893 as the Bertillon Classification, which was rapidly adopted by several countries.

The ICD Coding

The World Health Organization issued a global reference document coding all diseases, injuries and deaths in 1949 and published the Manual of the International Classification of Diseases, Injuries and Causes of Death, nicknamed today the ICD system.


Originally practiced on a volunteer basis, the use of medical coding became mandatory in the United States in 1996, when the government passed the Health Insurance Portability and Accountability Act calling for total privacy of patients' information. Today, the U.S. system uses the Current Procedural Terminology system for outpatient services and Medicare and Medicaid for non-physician items. The Diagnosis-Related Group coding system sets reimbursement for hospitalization. Modern medical codes tell insurance companies how much to reimburse your physician for the service that he performed, writes Anne B. Casto, who works at Ohio State University. Interestingly, the first use of medical coding had a different purpose.