Calcium deposit within a bursa at an unspecified anatomical site, classified under other bursopathies in the musculoskeletal chapter.

Documentation tips

What should appear in the chart to support M71.40.

Source · Editorial brief grounded in 5 cited references ↓

• Record the exact bursa location by name (e.g., olecranon, trochanteric, prepatellar) — if the site is known, use a site-specific M71.4x code instead of M71.40.
• Document imaging findings that confirm calcification: plain radiograph or ultrasound showing calcific deposits within the bursal sac, including size and density if reported.
• Note the etiology as non-mechanical (not related to overuse or pressure) to support M71.4x over M70.- codes; document absence of repetitive mechanical cause when applicable.
• If the shoulder is the affected side, explicitly route to M75.3 (Calcific tendinitis of shoulder) — the Excludes2 note at M71.4 prohibits use of M71.40 for shoulder bursal calcium deposits.
• For injection procedures, document the specific bursa injected, the agent used, and the clinical indication to link the diagnosis code to the CPT procedure code for medical necessity.

Related CPT procedures

Procedure codes commonly billed with M71.40. 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 M71.40 and adjacent codes.

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

• Using M71.40 for shoulder calcific bursitis — M75.3 is required; the Excludes2 note at M71.4 explicitly excludes calcium deposit in the bursa of the shoulder.
• Defaulting to M71.40 when the site is documented in the note — if the provider names any specific joint or anatomical location, a site-specific M71.4x code (e.g., M71.421 for right elbow) must be used.
• Confusing M71.40 with M70.- bursitis codes — mechanical or overuse bursitis belongs in M70, not M71; the M71 category is for non-mechanical causes including calcium deposits.
• Assigning M71.40 when enthesopathy is the actual diagnosis — enthesopathies code to M76–M77, which are Type 1 Excluded from M71.
• Failing to query the provider when site is undocumented — M71.40 is an unspecified code acceptable only when the site is truly unknown, not when documentation is simply incomplete.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

Sibling codes

Other billable codes under M71.4 (laterality / anatomic variants).