M86.9 Osteomyelitis, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Infection of bone NOS
• Periostitis without osteomyelitis

Applies from M86 Osteomyelitis

Excludes1 (never code together)

• osteomyelitis due to:
• echinococcus (B67.2)
• gonococcus (A54.43)
• salmonella (A02.24)

Excludes2 (not included here)

• ostemyelitis of:
• orbit (H05.0-)
• petrous bone (H70.2-)
• vertebra (M46.2-)

Use additional code

• code (B95-B97) to identify infectious agent
• code to identify major osseous defect, if applicable (M89.7-)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
• CMS-HCC V22: HCC 39 — Bone/Joint/Muscle Infections/Necrosis
• ESRD V24: HCC 39

MS-DRG index

Defines the logic of DRG(s) 456-458 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 730.20 Unspecified osteomyelitis, site unspecified (approximate)
• 730.30 Periostitis, without mention of osteomyelitis, site unspecified (approximate)
• 730.90 Unspecified infection of bone, site unspecified (approximate)
• 730.98 Unspecified infection of bone, other specified sites (approximate)

Code annotations containing back-references to M86.9

Back-references to M86

• Code First: M89.7 Major osseous defect ("osteomyelitis (M86.-)")

Diagnosis Index entries for M86.9

• Osteomyelitis (general) (infective) (localized) (neonatal) (purulent) (septic) (staphylococcal) (streptococcal) (suppurative) (with periostitis)

Nearby codes

• M86.8X5 Other osteomyelitis, thigh
• M86.8X6 Other osteomyelitis, lower leg
• M86.8X7 Other osteomyelitis, ankle and foot
• M86.8X8 Other osteomyelitis, other site
• M86.8X9 Other osteomyelitis, unspecified sites
• M86.9 Osteomyelitis, unspecified (this code)