What is icd-9 coding?

ICD-9 coding, or International Classification of Diseases, 9th Revision, is a system of alphanumeric codes used to classify diseases and injuries for the purposes of reimbursement, research, and public health surveillance. It was developed by the World Health Organization (WHO) and is the most widely used system of disease classification in the world.

ICD-9 codes consist of a series of three to five digits, with each digit representing a different level of specificity. The first digit represents the chapter, the second digit represents the category, the third digit represents the subcategory, and the fourth and fifth digits represent specific diagnoses. For example, the code 486 represents pneumonia, with 4 representing diseases of the respiratory system, 8 representing pneumonia, and 6 representing unspecified pneumonia.

ICD-9 codes are used by healthcare providers, insurance companies, and government agencies to track and manage health data. They are also used for research purposes, such as studying the incidence and prevalence of diseases, and for public health surveillance, such as tracking the spread of infectious diseases.

ICD-9 was replaced by ICD-10 in October 2015, but it is still used in some settings.