ICD-10 Code M00.80 – Arthritis due to other bacteria, unspecified joint (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00.80 – Arthritis due to other bacteria, unspecified joint
What it is
This code identifies bacterial arthritis affecting a joint when the organism is not one of the specific organisms named in other codes and the joint is not specified. It indicates an infectious process within a joint, not chronic degenerative arthritis.
Clinical signs
Typical findings include acute joint pain, swelling, warmth, and limited range of motion. Fever or elevated inflammatory markers may occur, but clinical features vary; refer to documentation.
When to use this code
Use M00.80 when the provider documents arthritis caused by another specified bacterium and does not name the joint involved. Apply it only when the record supports an infectious arthritis diagnosis, not when the note describes nonspecific joint pain or inflammation.
If the chart identifies the exact joint, select the more specific code for that site. If the causative organism is not documented, check documentation before assigning this code.
Do not use for
Do not use this code for viral, fungal, or gonococcal arthritis, or for septic arthritis coded elsewhere. It is also wrong for noninfectious arthritis such as osteoarthritis or rheumatoid arthritis.
Coding tip
Confirm both the bacterial cause and the unspecified-joint documentation before coding; otherwise, query for the missing details.