All codes in the International Classification of Diseases, 10th Revision, Clinical Modification are:

• A. Alphanumeric
• B. Numeric
• C. Alpha
• D. Either alpha or numeric

Answer: (A)

ICD-10-CM codes use a mix of letters and numbers. The code starts with a letter, then two digits to form the broad category, and after a decimal point there can be up to four more characters that can be digits or letters. This alphanumeric structure lets the coding system be both concise and highly specific, including details like subcategories and encounter types. For example, codes such as E11.65 or A41.9 illustrate the combination of letters and numbers throughout the code. Since every code includes both letters and numbers, it is not purely numeric or purely alphabetic, and it isn’t correct to say the codes are either alpha or numeric.