ICD-10 Code M00.859 – Arthritis due to other bacteria, unspecified hip (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00.859 – Arthritis due to other bacteria, unspecified hip
What it is
This code identifies bacterial arthritis in the hip when the organism is not one of the specifically listed bacteria and the hip side is not documented. It reflects an infectious joint process, not degenerative or inflammatory arthritis.
Clinical signs
Typical findings include acute hip pain, limited range of motion, swelling, warmth, and difficulty bearing weight. Fever or elevated inflammatory markers may occur, but clinical features vary; refer to documentation.
When to use this code
Use this code when the record documents septic or infectious arthritis of the hip caused by “other bacteria” and laterality is not specified. It is also appropriate when the provider confirms bacterial joint infection but does not name the organism in a way that maps to a more specific code.
Check documentation if the note only says arthritis, joint pain, or suspected infection without a confirmed bacterial cause. Code the documented hip laterality when available; otherwise, unspecified hip is correct.
Do not use for
Do not use this code for noninfectious arthritis, such as osteoarthritis, rheumatoid arthritis, or crystal arthropathy. Do not use it when the organism is not bacterial or when a more specific organism code is documented.
Coding tip
Confirm both the infectious cause and the hip laterality in the provider note before assigning M00.859.