ICD-10 Code M00.121 – Pneumococcal arthritis, right elbow (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M00.121 – Pneumococcal arthritis, right elbow
What it is
M00.121 identifies a pneumococcal infection in the right elbow joint. Use it when documentation specifies Streptococcus pneumoniae as the cause of septic arthritis in that joint.
Clinical signs
Typical findings include a painful, swollen, warm joint with limited range of motion. Clinical features vary; refer to documentation for evidence of acute infectious arthritis and the organism involved.
When to use this code
Use this code when the provider documents pneumococcal arthritis affecting the right elbow, or septic arthritis of that joint caused by pneumococcus. It is appropriate when laterality and organism are both clearly identified in the record.
If the note only says “arthritis” or “septic arthritis” without the causative organism, check documentation before assigning M00.121. Make sure the right elbow is specifically named, not another joint.
Do not use for
Do not use this code for noninfectious arthritis, unspecified septic arthritis, or pneumococcal infection at a different site. Check documentation if the organism or joint laterality is unclear.
Coding tip
Confirm both the pneumococcal cause and right elbow laterality in the provider note before coding.