Monoarthritis, not elsewhere classified, unspecified site

This code represents inflammation affecting a single joint that is not attributable to another specific arthritic condition. It indicates a localized joint inflammation without a definitive underlying cause identified or documented.

Use this code when documentation specifies monoarthritis without further etiological detail or when the specific type of arthritis cannot be classified elsewhere. It is appropriate when the physician's diagnosis is "monoarthritis, unspecified" or "monoarthritis NOS."

• Avoid using this code if a more specific type of monoarthritis (e.g., infectious, traumatic, crystal-induced) is documented.
• Query the provider for a more specific diagnosis if possible, as this code represents an unspecified condition.
• Do not use for polyarthritis; refer to codes for multiple joint involvement.