M05.122 ICD-10-CM Code: Rheumatoid lung disease with rheumatoid arthritis of left elbow
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Inflammatory polyarthropathies (M05-M14)
M05.122
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceRheumatoid lung disease with rheumatoid arthritis of left elbow
Rheumatoid arthritis of the left elbow combined with lung disease caused by the rheumatoid condition.
Buddy Insight
Represents severe systemic rheumatoid arthritis with both left elbow joint involvement and pulmonary complications, indicating advanced disease with extra-articular manifestations.
CMS-HCC V28
MappedHCC 93
RAF 0.175
CMS-HCC V24
MappedHCC 40
RAF 0.307
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 40
RAF 0.0
RXHCC
MappedHCC 83
RAF 0.0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for M05.122 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for M05.122 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for M05.122 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for M05.122 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for M05.122 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for M05.122 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for M05.122 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is M05.122 an HCC code?
Yes. M05.122 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under the CMS-HCC V28 risk adjustment model (and Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for M05.122
For M05.122to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- 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
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed M05.122 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
M05.122 is the ICD-10-CM diagnosis code for rheumatoid lung disease with rheumatoid arthritis of left elbow. Rheumatoid arthritis of the left elbow combined with lung disease caused by the rheumatoid condition. M05.122 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering inflammatory polyarthropathies (m05-m14).
Under the CMS-HCC V28 risk adjustment model, M05.122 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease (HCC 93) with a community, non-dual, aged base RAF weight of 0.175. Under the older V24 model, M05.122 mapped to the same category but with a base RAF weight of 0.307, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Requires documentation of both elbow joint involvement AND rheumatoid lung disease; both conditions must be present. Because M05.122 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for M05.122 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Requires documentation of both elbow joint involvement AND rheumatoid lung disease; both conditions must be present
- •Verify laterality is clearly documented as left elbow in the medical record
Clinical Significance
Represents severe systemic rheumatoid arthritis with both left elbow joint involvement and pulmonary complications, indicating advanced disease with extra-articular manifestations. This combination requires coordinated rheumatology and pulmonology management with intensive immunosuppressive therapy.
Documentation Requirements
- ✓Confirmed rheumatoid arthritis with positive serological testing
- ✓Documentation of left elbow joint involvement with inflammatory findings
- ✓Evidence of rheumatoid-related lung disease through appropriate studies
- ✓Specific notation of left-sided elbow involvement
- ✓Clinical assessment establishing connection between RA and lung pathology
- ✓Current disease activity assessment and treatment plan
- ✓Pulmonary function monitoring and respiratory symptom documentation
Commonly Confused Codes
- •M05.121: Rheumatoid lung disease with RA of right elbow (different laterality)
- •M05.129: Rheumatoid lung disease with RA of unspecified elbow (laterality unknown)
- •M06.022: Rheumatoid arthritis of left elbow without lung disease
- •M05.132: Rheumatoid lung disease with RA of left wrist (different joint)
- •M05.142: Rheumatoid lung disease with RA of left hand (different anatomical location)