2026 ICD-10-CM Diagnosis Code M02.359Reiter's disease, unspecified hip
ICD-10-CM Codes›M00–M99›M00-M02›M02
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 94
- Not Chronic
M02.359 is a billable ICD-10-CM diagnosis code for Reiter's disease, unspecified hip. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 545 through 547. 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 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, M02.359 maps to CMS-HCC Category 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders) under the V28 model, adding a risk factor of about 0.268 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 M02.359.
Medicare Risk Adjustment (HCC)Billing
M02.359 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.
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 M02.359 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About M02.359Overview
What is the ICD-10 code for Reiter's disease, unspecified hip?
The ICD-10-CM code for Reiter's disease, unspecified hip is M02.359 (sometimes written as M02359). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is M02.359 (Reiter's disease, hip) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report Reiter's disease, unspecified hip on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M02.359 group to?
When Reiter's disease, unspecified hip is the principal diagnosis on an inpatient stay, it groups to MS-DRG 545, 546, 547, with relative weights from 0.8362 to 2.4817 depending on complications. Higher weights mean higher Medicare reimbursement.
Is M02.359 a CC or MCC?
CMS lists M02.359 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.
What is the ICD-9 equivalent of M02.359?
Under the General Equivalence Mappings, Reiter's disease, unspecified hip converts to ICD-9-CM 099.3 (Reiter's disease) and 711.15 (reiter arthritis-pelvis). The mapping is approximate, so confirm the match fits the documentation.
What HCC is M02.359?
M02.359 (Reiter's disease, unspecified hip) maps to CMS-HCC Category 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders), commonly written as HCC 94, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 40 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 83.
Does M02.359 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, M02.359 adds a risk adjustment factor of about 0.268 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.196 to 0.297 depending on the payment segment). A more severe related category (HCC 93) supersedes it when both are reported. See the full factor table on the HCC 94 category page.
