ICD-10 Code M00 – Pyogenic arthritis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00 – Pyogenic arthritis
What it is
M00 identifies pyogenic arthritis, a joint infection caused by bacteria. Use it when the record shows septic or purulent arthritis affecting one or more joints.
Clinical signs
Typical findings include joint pain, swelling, warmth, reduced range of motion, and tenderness. Fever or elevated inflammatory markers may occur, but clinical features vary; refer to documentation.
When to use this code
Use M00 when the provider documents pyogenic, septic, or purulent arthritis and does not assign a more specific organism-based code. It may apply to acute infectious arthritis involving a single joint or multiple joints. Check documentation for the affected joint and any causal organism.
Do not use for
Do not use this code for noninfectious inflammatory arthritis, traumatic joint effusion, or chronic degenerative joint disease. If the record identifies a specific organism or another diagnosis, code that instead.
Coding tip
Look for the documented site and causative organism, because M00 is often a category that requires greater specificity.