ICD-10 Code M01.X9 – Direct infection of multiple joints in infectious and parasitic diseases classified elsewhere (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M01.X9 – Direct infection of multiple joints in infectious and parasitic diseases classified elsewhere
What it is
This code identifies direct infection involving multiple joints when the underlying infectious or parasitic disease is classified elsewhere. Use it when the joint infection is part of a broader documented infection, not a primary joint disorder.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include painful, swollen, warm joints with limited motion affecting more than one joint, along with evidence of an active infectious or parasitic condition.
When to use this code
Use M01.X9 when the record clearly states direct infection of multiple joints and links it to an infectious or parasitic disease coded elsewhere. This is appropriate when the provider documents the joint involvement as secondary to the underlying infection. Check documentation for the specific causal organism or primary disease code.
Do not use for
Do not use this code for isolated arthritis, degenerative joint disease, or septic arthritis without documentation of multiple-joint direct infection. If the infection source or relation to another disease is unclear, check documentation.
Coding tip
Code the underlying infectious or parasitic condition first, then assign M01.X9 only when the provider documents direct infection of multiple joints.