M86.39 maps to CMS-HCC V28 92. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupM86.39

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Other osteopathies (M86-M90)

M86.39

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Chronic multifocal osteomyelitis, multiple sites

A chronic bone infection affecting multiple areas throughout the body in more than one anatomical region.

Buddy Insight

Chronic multifocal osteomyelitis affecting multiple sites represents the most severe form of this condition, with infection involving bones across different anatomical regions simultaneously.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 92

Bone/Joint/Muscle/Severe Soft...

Coefficient HCC 92: 0.479 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 055

HHS-HCC 055 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 39

Bone/Joint/Muscle Infections/...

Code-level coefficient reference

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

M86Osteomyelitis M86.3Chronic multifocal osteomyelitis M86.39Chronic multifocal osteomyelitis, multiple sites

Inclusion Terms

Official

No inclusion terms are included in this display for M86.39. Check the code and parent instructions in the Code Book.

Excludes 2

Official

arthropathic psoriasis (L40.5-)Inherited from M00-M99, M86
certain conditions originating in the perinatal period (P04-P96)Inherited from M00-M99, M86
certain infectious and parasitic diseases (A00-B99)Inherited from M00-M99, M86
compartment syndrome (traumatic) (T79.A-)Inherited from M00-M99, M86
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from M00-M99, M86
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from M00-M99, M86
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from M00-M99, M86
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from M00-M99, M86
neoplasms (C00-D49)Inherited from M00-M99, M86
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from M00-M99, M86
ostemyelitis of:Inherited from M00-M99, M86
orbit (H05.0-)Inherited from M00-M99, M86
petrous bone (H70.2-)Inherited from M00-M99, M86
vertebra (M46.2-)Inherited from M00-M99, M86

Related Codes

Official

M86.30Chronic multifocal osteomyelitis, unspecified site M86.31Chronic multifocal osteomyelitis, shoulder M86.32Chronic multifocal osteomyelitis, humerus M86.33Chronic multifocal osteomyelitis, radius and ulna M86.34Chronic multifocal osteomyelitis, hand

Includes

Official

No Includes notes are included in this display for M86.39. Check the code and parent instructions in the Code Book.

Excludes 1

Official

postprocedural osteopathies (M96.-)Inherited from M86-M90, M86
osteomyelitis due to:Inherited from M86-M90, M86
echinococcus (B67.2)Inherited from M86-M90, M86
gonococcus (A54.43)Inherited from M86-M90, M86
salmonella (A02.24)Inherited from M86-M90, M86

Code First

Official

No Code First sequencing instructions are included in this display for M86.39. Check the code and parent instructions in the Code Book.

Use Additional

Official

code (B95-B97) to identify infectious agentInherited from M86
code to identify major osseous defect, if applicable (M89.7-)Inherited from M86

Code Also

Official

No Code Also instructions are included in this display for M86.39. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation of involvement in multiple distinct anatomical sites

Evidence of chronicity across all affected sites (>6 weeks or recurrent)

Confirmation of multifocal pattern within multiple bone regions

Imaging studies showing chronic changes at multiple locations

MEAT Support

HCC Buddy guidance

Documentation of involvement in multiple distinct anatomical sites

Evidence of chronicity across all affected sites (>6 weeks or recurrent)

Confirmation of multifocal pattern within multiple bone regions

Imaging studies showing chronic changes at multiple locations

Audit Caution

HCC Buddy guidance

Using single-site codes when multiple regions are involved

Missing the extensive nature of multi-site involvement

Confusing with acute presentations of multi-site osteomyelitis

Using when involvement is limited to single anatomical region

Common Mistakes

HCC Buddy guidance

M86.30 — Chronic multifocal osteomyelitis, unspecified site, single region

M86.69 — Other chronic osteomyelitis, multiple sites, lacks multifocal component

M86.19 — Acute osteomyelitis, multiple sites, differs by chronicity

M86.49 — Chronic osteomyelitis with draining sinus, multiple sites

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is M86.39 an HCC code?

Yes. M86.39 (Chronic multifocal osteomyelitis, multiple sites) maps to HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.479. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: M86.39 is billable and maps to V28 HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: M86.39
Description: Chronic multifocal osteomyelitis, multiple sites
HCC (V28): HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis
RAF reference coefficient: 0.479
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 92, Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis

0.479

ESRDHCC 39, Bone/Joint/Muscle Infections/Necrosis

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work M86.39 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for M86.39

For M86.39, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

M86.39 is the ICD-10-CM diagnosis code for chronic multifocal osteomyelitis, multiple sites. A chronic bone infection affecting multiple areas throughout the body in more than one anatomical region. M86.39 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering other osteopathies (m86-m90).

Under the CMS-HCC V28 risk adjustment model, M86.39 maps to Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis (HCC 92) with a source-labeled community, non-dual, aged reference coefficient of 0.479. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This code indicates involvement of multiple sites across different body regions. For M86.39, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for M86.39 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code indicates involvement of multiple sites across different body regions
•Document all affected sites and consider using additional codes if specific regions are clearly identified

Clinical Significance

Chronic multifocal osteomyelitis affecting multiple sites represents the most severe form of this condition, with infection involving bones across different anatomical regions simultaneously. This diagnosis indicates extensive disease requiring comprehensive, multidisciplinary management with significant morbidity risk.

Documentation Requirements

✓Documentation of involvement in multiple distinct anatomical sites
✓Evidence of chronicity across all affected sites (>6 weeks or recurrent)
✓Confirmation of multifocal pattern within multiple bone regions
✓Imaging studies showing chronic changes at multiple locations
✓Comprehensive assessment of functional impact across body regions
✓Laboratory markers consistent with systemic chronic infection
✓Treatment documentation addressing multiple site complexity
✓Provider assessment confirming extensive multifocal osteomyelitis

Commonly Confused Codes

•M86.30: Chronic multifocal osteomyelitis, unspecified site, single region
•M86.69: Other chronic osteomyelitis, multiple sites, lacks multifocal component
•M86.19: Acute osteomyelitis, multiple sites, differs by chronicity
•M86.49: Chronic osteomyelitis with draining sinus, multiple sites
•M86.59: Other chronic hematogenous osteomyelitis, multiple sites