M71.00 identifies an infectious abscess within a bursa when the affected site is not documented or cannot be determined from available records.

Documentation tips

What should appear in the chart to support M71.00.

Source · Editorial brief grounded in 5 cited references ↓

• Document the specific anatomic site of the bursa (e.g., olecranon, prepatellar, trochanteric) — 'unspecified site' should only remain when location is genuinely unknown after review of all available records.
• Record the causative organism when identified by culture; pair M71.00 with B95.- or B96.- per the parent code's 'Use Additional Code' instruction.
• Note whether the infection is new (initial presentation) versus recurrent, and whether the patient has undergone prior aspiration or antibiotic treatment — this supports medical necessity for surgical drainage.
• Distinguish infectious bursitis from inflammatory or overuse bursitis in the assessment: use terms like 'septic bursitis' or 'bursal abscess' rather than 'bursitis' alone to prevent miscoding to M70.-.
• If laterality is known, it must be captured in the child code — M71.00 is only appropriate when site is truly unspecified, not when laterality alone is unspecified.

Related CPT procedures

Procedure codes commonly billed with M71.00. 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 M71.00 and adjacent codes.

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

• Defaulting to M71.00 when the clinical note names the site: any documented location requires a site-specific M71.0x code; M71.00 is not a legitimate shortcut for incomplete coding.
• Failing to append a causative organism code (B95.- or B96.-) when culture results are available — this is a 'Use Additional Code' directive, not optional guidance.
• Confusing septic bursitis (M71.0x) with overuse bursitis (M70.-): the M71 category explicitly excludes bursitis due to use, overuse, or pressure, so check the clinical note for infectious versus mechanical etiology before selecting a code.
• Using M71.00 for a known-site abscess simply because laterality is undocumented — if the site is known but laterality is not, use the appropriate unspecified-laterality child code (e.g., M71.019 for unspecified shoulder), not M71.00.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

Sibling codes

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