How many characters can ICD-10-CM codes contain at maximum?

ICD-10-CM codes can contain a maximum of seven characters. This coding system is designed to allow for both specificity and flexibility in medical coding. The structure of an ICD-10-CM code includes an alphanumeric character followed by up to six additional characters, which can be either letters or numbers.

The first character is always a letter, while the second character is typically a number. Characters three through seven can be either letters or numbers, depending on the specific code. This seven-character format enables coders to create detailed and precise codes reflective of a wide range of medical conditions.

The other options, which suggest fewer characters, do not accommodate the full range of coding complexities needed in today's medical documentation and billing processes.