What is the major difference between ICD-9 and ICD-10?

• A. An increase in the number of codes
• B. A decrease in the number of codes
• C. No change in the number of codes
• D. ICD-9 has more dx codes than ICD-10

Answer: (A)

The major difference is the dramatic expansion in the number of codes from ICD-9 to ICD-10, allowing far greater specificity. ICD-10 uses alphanumeric codes that can be up to seven characters long, and it distinguishes between diagnosis coding (ICD-10-CM) and procedure coding (ICD-10-PCS). This results in tens of thousands of diagnosis codes and many thousands of procedure codes, compared with roughly fourteen thousand diagnosis codes and only a few thousand procedure codes in ICD-9-CM. The larger code set enables more precise documentation of conditions, procedures, laterality, encounter type, and other details, improving billing accuracy and data quality. The other statements don’t fit because ICD-10 does not decrease or keep the same number of codes, and ICD-9 does not have more diagnosis codes than ICD-10.