Infective myositis affecting skeletal muscle at multiple anatomic sites simultaneously, caused by a bacterial, viral, fungal, or parasitic organism.

Documentation tips

What should appear in the chart to support M60.09.

Source · Editorial brief grounded in 6 cited references ↓

• Explicitly name each affected muscle or muscle group and its anatomic location — 'multiple sites' must be supported by discrete clinical findings at more than one region.
• Document the suspected or confirmed causative organism (bacterial species, virus, fungus, or parasite) to support the required B95–B97 companion code.
• Record diagnostic workup results — cultures, MRI findings showing muscle edema or abscess, elevated CK or ESR — to substantiate an infectious etiology rather than inflammatory or traumatic myositis.
• Note any underlying immunocompromising conditions (HIV, diabetes, steroid use) that increase pyomyositis risk; these may qualify as MCCs affecting DRG weight.
• Distinguish tropical pyomyositis from other infective myositis in the note if relevant — it is an Applicable To inclusion under M60.0 and supports M60.09 when multiple muscles are involved.

Related CPT procedures

Procedure codes commonly billed with M60.09. 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 M60.09 and adjacent codes.

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

• Using M60.09 without appending a B95–B97 organism code violates the parent-level 'Use Additional Code' instruction and risks claim rejection or audit findings.
• Defaulting to M60.09 when only one body region is documented — the correct code is the site-specific M60.0xx child code; M60.09 requires clinically documented multiple sites.
• Confusing M60.09 with M60.08 (other site) — 'other site' applies to a single non-listed anatomic location, not to multiple concurrent sites.
• Coding M60.09 for inclusion body myositis (IBM) — IBM is excluded from M60 entirely and must be coded G72.41.
• Sequencing M60.09 as a secondary code when it is the principal diagnosis driving the encounter — infective myositis is the etiology, not a manifestation, so it sequences first with the organism code following.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

Sibling codes

Other billable codes under M60.0 (laterality / anatomic variants).