What is ICD-10?

• A. They classify professional services provided by a clinician
• B. They will contain 3 to 7 characters and the first character will always be a letter
• C. They begin with a digit
• D. They are used to code hospital revenue cycles

Answer: (B)

ICD-10 codes are alphanumeric identifiers used to classify diseases and health problems, and they follow a specific structure: the code begins with a letter and is 3 to 7 characters long. This pattern defines how diagnoses and related conditions are coded, with a decimal often used after the third character to separate category from subcategory. Because of this established format, the description stating that codes will contain 3 to 7 characters and that the first character is always a letter best captures what ICD-10 codes look like.

Other statements miss the coding structure: professional services are typically coded with CPT, not ICD-10; codes do not begin with a digit; and while ICD-10 codes are used in billing, saying they are for hospital revenue cycles doesn’t define the code structure themselves.