Medical billers and coders primarily use codes from two manuals: the "International Classification of Diseases (ICD)" manual and the "Current Procedural Terminology (CPT)" manual. These books contain thousands of numerical and alphanumerical codes to apply to insurance forms.
The CPT book lists codes for reporting medical services and procedures, including diagnostic, laboratory, radiology, surgical and many others.
The ICD manual includes codes that identify the particular diagnosis. These codes describe a disease or condition. The United States uses the ninth revision, or ICD-9, but many countries use the 10th revision.
The CPT manual is published by the American Medical Association, while the ICD book is published by the World Health Organization.
As many as four ICD-9 codes can be linked to one CPT code on a standard HCFA-1500 insurance claim form.
Number of Codes
The CPT manual has about 7,800 codes, compared with 24,000 in the ICD-9. The ICD-10 has more than 200,000 codes.