While there are no free online books listing the most up-to-date ICD-9 codes, ICD9Data.com provides a searchable database of ICD-9 medical codes. The site also offers a conversion tool to help with the transition from ICD-9 to ICD-10.
All health care providers that are covered by the Health Insurance Portability Accountability Act are required to transition from ICD-9 to ICD-10 medical codes for diagnosis and inpatient procedures as of Oct. 1, 2015, as the Centers for Medicare and Medicaid Services explains. Medical billing codes for outpatient and physician services are not affected by the change. However, all insurance companies and health plans must participate in the change.