Infectious abscess affecting the bursal sacs at two or more anatomically distinct sites simultaneously, classified under other bursopathies in the musculoskeletal chapter.

Documentation tips

What should appear in the chart to support M71.09.

Source · Editorial brief grounded in 4 cited references ↓

• Name each affected bursa explicitly (e.g., 'prepatellar bursa right knee and olecranon bursa left elbow') — vague multi-site language alone won't defend M71.09 on audit.
• Document the infectious nature of the abscess: purulent aspirate, positive culture, or clinical findings consistent with suppurative bursitis distinguish M71.09 from non-infectious bursopathy codes.
• Record any imaging findings (ultrasound, MRI) that confirm fluid collection with abscess characteristics at each named site.
• If the causative organism is identified, add a pathogen code (B95–B98) as a secondary diagnosis per ICD-10-CM 'use additional code' instructions.
• Capture MCC-qualifying comorbidities in the encounter note — they determine DRG 557 vs. 558 and directly affect facility payment.

Related CPT procedures

Procedure codes commonly billed with M71.09. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

Common coding pitfalls

The recurring mistakes coders make with M71.09 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

• Defaulting to M71.09 when only one bursa is infected — if a single site is documented, use the site-specific lateralized M71.0x code instead.
• Confusing M71.0x (infectious abscess of bursa) with M70.x (use/overuse bursitis) — if the note says 'bursitis from repetitive motion' without abscess documentation, M71.09 is wrong.
• Assigning M71.09 when the abscess is in surrounding soft tissue rather than within the bursa itself — cutaneous abscess defaults to L02.x, not M71.
• Omitting the secondary organism code when culture results are available, leaving a compliance gap and reducing clinical specificity on the claim.
• Using M71.09 for bilateral involvement of the same bursa type (e.g., both olecranon bursae) when bilateral site-specific codes exist — verify whether a bilateral or multi-site code is more precise for the documented anatomy.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

Sibling codes

Other billable codes under M71.0 (laterality / anatomic variants).