ICD-10 Code M00.861 – Arthritis due to other bacteria, right knee (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00.861 – Arthritis due to other bacteria, right knee
What it is
This code identifies a bacterial infection causing inflammation in the right knee joint. Use it when documentation specifies arthritis due to other bacteria, not a more specific organism or another joint.
Clinical signs
Typical findings include a painful, swollen, warm knee with limited range of motion and possible joint effusion. Clinical features vary; refer to documentation for the organism and whether the infection is acute or confirmed.
When to use this code
Use M00.861 when the provider documents bacterial arthritis of the right knee caused by other bacteria and the right side is clearly identified. This applies to confirmed infectious arthritis, not nonspecific knee pain or inflammatory arthritis without bacterial cause. Check documentation if the organism is not stated.
Do not use for
Do not use this code for left or unspecified knee involvement, viral or fungal joint infection, or noninfectious arthritis such as osteoarthritis or rheumatoid arthritis. If the record does not confirm bacterial cause, check documentation.
Coding tip
Verify laterality and the documented bacterial etiology before assigning this code.