What is ICD-10 code M00.039?

M00.039 is the ICD-10-CM diagnosis code for Staphylococcal arthritis, unspecified wrist. A bacterial infection of the wrist joint caused by Staphylococcus bacteria when the specific side is not identified. It belongs to the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99). M00.039 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. M00.039 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. M00.039 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. M00.039 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does M00.039 map to under V28?

M00.039 maps to CMS-HCC V28 HCC 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM M00.039: Staphylococcal arthritis

M00.039 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 · HCC Buddy coding tools

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Code lookupM00.039

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Infectious arthropathies (M00-M02)

M00.039

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

Staphylococcal arthritis, unspecified wrist

A bacterial infection of the wrist joint caused by Staphylococcus bacteria when the specific side is not identified.

Buddy Insight

Staphylococcal arthritis of the unspecified wrist is a serious bacterial joint infection (septic arthritis) requiring emergency treatment to prevent permanent joint damage.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 92

Bone/Joint/Muscle/Severe Soft...

Code-level coefficient reference

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

M00.0Staphylococcal arthritis and polyarthritis M00.03Staphylococcal arthritis, wrist M00.039Staphylococcal arthritis, unspecified wrist

Inclusion Terms

Official

Staphylococcal arthritis of carpal bonesInherited from M00.03

Excludes 2

Official

arthropathic psoriasis (L40.5-)Inherited from M00-M99, M00
certain conditions originating in the perinatal period (P04-P96)Inherited from M00-M99, M00
certain infectious and parasitic diseases (A00-B99)Inherited from M00-M99, M00
compartment syndrome (traumatic) (T79.A-)Inherited from M00-M99, M00
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from M00-M99, M00
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from M00-M99, M00
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from M00-M99, M00
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from M00-M99, M00
neoplasms (C00-D49)Inherited from M00-M99, M00
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from M00-M99, M00
infection and inflammatory reaction due to internal joint prosthesis (T84.5-)Inherited from M00-M99, M00

Related Codes

Official

M00.031Staphylococcal arthritis, right wrist M00.032Staphylococcal arthritis, left wrist

Includes

Official

No Includes notes are included in this display for M00.039. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for M00.039. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for M00.039. Check the code and parent instructions in the Code Book.

Use Additional

Official

code (B95.61-B95.8) to identify bacterial agentInherited from M00.0

Code Also

Official

No Code Also instructions are included in this display for M00.039. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation identifying Staphylococcus as the causative organism (culture results, clinical diagnosis, or documented species)

Documentation of the affected joint with specific anatomical site

Laterality (right, left) should be documented — query provider if not specified

Clinical findings supporting joint infection (joint effusion, warmth, erythema, limited range of motion, fever)

MEAT Support

HCC Buddy guidance

Provider documentation identifying Staphylococcus as the causative organism (culture results, clinical diagnosis, or documented species)

Documentation of the affected joint with specific anatomical site

Laterality (right, left) should be documented — query provider if not specified

Clinical findings supporting joint infection (joint effusion, warmth, erythema, limited range of motion, fever)

Audit Caution

HCC Buddy guidance

Coding staphylococcal arthritis without confirmed Staphylococcus identification — if organism is unknown, use M00.9 (pyogenic arthritis, unspecified) instead

Failing to differentiate between Staphylococcus aureus and other Staphylococcus species when documentation is available — M00.0x covers all Staphylococcus species

Not coding associated conditions such as sepsis (A41.0x for Staphylococcal sepsis) or osteomyelitis when documented alongside the septic arthritis

Using unspecified laterality when the medical record documents a specific side — always query for laterality before defaulting to unspecified

Common Mistakes

HCC Buddy guidance

M00.13x — Pneumococcal arthritis of same joint site; differs by causative organism (Pneumococcus vs. Staphylococcus)

M00.23x — Streptococcal arthritis of same joint site; differs by causative organism (Streptococcus vs. Staphylococcus)

M00.83x — Arthritis due to other bacteria at same joint site; use when organism is identified but not Staphylococcus

M00.9 — Pyogenic arthritis, unspecified; use only when causative organism cannot be identified

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 M00.039 an HCC code?

Yes. M00.039 (Staphylococcal arthritis, unspecified wrist) 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: M00.039 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: M00.039
Description: Staphylococcal arthritis, unspecified wrist
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 M00.039 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for M00.039

For M00.039, 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

M00.039 is the ICD-10-CM diagnosis code for staphylococcal arthritis, unspecified wrist. A bacterial infection of the wrist joint caused by Staphylococcus bacteria when the specific side is not identified. M00.039 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering infectious arthropathies (m00-m02).

Under the CMS-HCC V28 risk adjustment model, M00.039 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. No V24 mapping is shown for M00.039; use the applicable model and payment year when reviewing the V28 mapping. 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 unspecified code should be avoided when possible; attempt to clarify laterality with provider. For M00.039, 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 M00.039 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This unspecified code should be avoided when possible; attempt to clarify laterality with provider
•Review imaging reports or clinical notes for any indication of which wrist is affected

Clinical Significance

Staphylococcal arthritis of the unspecified wrist is a serious bacterial joint infection (septic arthritis) requiring emergency treatment to prevent permanent joint damage. Staphylococcus is the most common causative organism in septic arthritis, and infection of the wrist joint carries risks of cartilage destruction, osteomyelitis, and systemic sepsis. Accurate site-specific coding is essential for risk adjustment and reflects the high acuity and resource needs of this condition.

Documentation Requirements

✓Provider documentation identifying Staphylococcus as the causative organism (culture results, clinical diagnosis, or documented species)
✓Documentation of the affected joint with specific anatomical site
✓Laterality (right, left) should be documented — query provider if not specified
✓Clinical findings supporting joint infection (joint effusion, warmth, erythema, limited range of motion, fever)
✓Synovial fluid analysis results or culture and sensitivity reports when available
✓Treatment documentation (antibiotics, joint aspiration, surgical drainage/washout)
✓Assessment of whether the infection is acute or chronic, and whether it is a primary infection or secondary to another source

Commonly Confused Codes

•M00.13x: Pneumococcal arthritis of same joint site; differs by causative organism (Pneumococcus vs. Staphylococcus)
•M00.23x: Streptococcal arthritis of same joint site; differs by causative organism (Streptococcus vs. Staphylococcus)
•M00.83x: Arthritis due to other bacteria at same joint site; use when organism is identified but not Staphylococcus
•M00.9: Pyogenic arthritis, unspecified; use only when causative organism cannot be identified
•M00.031: Same condition, right side; use when right laterality is documented
•M00.032: Same condition, left side; use when left laterality is documented