ICD-10 Code M00.1 – Pneumococcal arthritis and polyarthritis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00.1 – Pneumococcal arthritis and polyarthritis
What it is
M00.1 identifies septic arthritis caused by pneumococcal infection, affecting one or more joints. Use it when documentation states pneumococcus is the organism responsible.
Clinical signs
Typical findings include acute joint pain, swelling, warmth, and limited range of motion. Clinical features vary; refer to documentation for the affected joint and confirmed organism.
When to use this code
Use M00.1 when the provider documents pneumococcal arthritis, pneumococcal polyarthritis, or septic arthritis due to Streptococcus pneumoniae. It may apply after aspiration, culture, or other documentation confirms the organism. If the record only says “infectious arthritis,” check documentation.
Do not use for
Do not use this code for noninfectious inflammatory arthritis or when another organism is specified. If the causative organism is not documented, check documentation before assigning M00.1.
Coding tip
Code the confirmed organism only when the record clearly links pneumococcus to the joint infection.