2026 ICD-10-CM Diagnosis Code A39.84Postmeningococcal arthritis
ICD-10-CM Codes›A00–B99›A30-A49›A39
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 92
- Chronic Condition
A39.84 is a billable ICD-10-CM diagnosis code for postmeningococcal arthritis. 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, 791, 793. 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 11 closely related codes. Coders also document this condition as arthropathy associated with bacterial disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Immune-mediated/reactive arthropathies.
For Medicare Advantage risk adjustment, A39.84 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
Medicare Risk Adjustment (HCC)Billing
A39.84 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 bacterial disease
- Post-bacterial arthropathy
- Postmeningococcal arthritis
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Meningococcal Infections
infections with bacteria of the species neisseria meningitidis.Neisseria meningitidis
a species of gram-negative, aerobic bacteria. it is a commensal and pathogen only of humans, and can be carried asymptomatically in the nasopharynx. when found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (meningitis, meningococcal). it is also found in venereal discharges and blood. there are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being a, b, c, y, and w-135. each serogroup can be further classified by serotype, serosubtype, and immunotype.
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 A39.84 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A39.84Overview
What is the ICD-10 code for postmeningococcal arthritis?
The ICD-10-CM code for postmeningococcal arthritis is A39.84 (sometimes written as A3984). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is A39.84 (Other meningococcal infections) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report postmeningococcal arthritis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does A39.84 group to?
When postmeningococcal arthritis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 548, 549, 550, 791, 793, with relative weights from 0.8741 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.
Is A39.84 a CC or MCC?
CMS lists A39.84 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 11 closely related codes in its exclusion list.
What is the ICD-9 equivalent of A39.84?
Under the General Equivalence Mappings, postmeningococcal arthritis converts to ICD-9-CM 036.82 (meningococc arthropathy). The mapping is approximate, so confirm the match fits the documentation.
What HCC is A39.84?
A39.84 (postmeningococcal arthritis) 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 A39.84 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, A39.84 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.
