2026 ICD-10-CM Diagnosis Code M02.80Other reactive arthropathies, unspecified site
ICD-10-CM Codes›M00–M99›M00-M02›M02
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 92
- Not Chronic
M02.80 is a billable ICD-10-CM diagnosis code for other reactive arthropathies, unspecified site. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 548 through 550. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 942 closely related codes. The code is a manifestation code that cannot be reported as the principal diagnosis and flagged as an unspecified code, since codes identifying laterality exist in the same family. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Immune-mediated/reactive arthropathies.
For Medicare Advantage risk adjustment, M02.80 maps to CMS-HCC Category 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis) under the V28 model, adding a risk factor of about 0.479 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for M02.80.
Medicare Risk Adjustment (HCC)Billing
M02.80 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Arthropathy associated with a hypersensitivity reaction
- Arthropathy associated with bacterial disease
- Arthropathy associated with nonspecific urethritis
- Mycobacterial postinfective arthritis
- Post-bacterial arthropathy
- Post-genitourinary infection reactive arthritis
- Post-tuberculous reactive arthritis
- Reactive arthritis due to and following mycobacteriosis
- Sequelae of tuberculosis
- Sexually acquired reactive arthritis
- Sexually acquired reactive arthritis of joint of pelvic wall
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Arthropathy See Also: Arthritis; M12.9
specified type NEC M02.80
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Infectious Arthritis
Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert M02.80 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M02.80Overview
What is the ICD-10 code for other reactive arthropathies, unspecified site?
The ICD-10-CM code for other reactive arthropathies, unspecified site is M02.80 (sometimes written as M0280). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is M02.80 (Other reactive arthropathies) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other reactive arthropathies, unspecified site on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M02.80 group to?
On inpatient claims, other reactive arthropathies, unspecified site maps to MS-DRG 548, 549, 550, with relative weights from 0.8741 to 1.9309 depending on complications. Higher weights mean higher Medicare reimbursement.
Is M02.80 a CC or MCC?
CMS lists M02.80 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 942 closely related codes in its exclusion list.
Can M02.80 be a principal diagnosis?
No. This is a manifestation code: other reactive arthropathies, unspecified site describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What HCC is M02.80?
M02.80 (other reactive arthropathies, unspecified site) maps to CMS-HCC Category 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis), commonly written as HCC 92, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 39 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does M02.80 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, M02.80 adds a risk adjustment factor of about 0.479 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.471 to 0.632 depending on the payment segment). HCC 92 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 92 category page.
