A54.42
BillableGonococcal arthritis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A54.42 an HCC code?
Yes. A54.42 maps to Bone/Joint/Muscle Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis 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 A54.42
For A54.42 to 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 A54.42 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
A54.42 is the ICD-10-CM diagnosis code for gonococcal arthritis. This is a joint infection caused by the bacterium Neisseria gonorrhoeae, which is transmitted through sexual contact. The infection causes inflammation, pain, and swelling in the affected joint or joints. A54.42 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering infections with a predominantly sexual mode of transmission (a50-a64).
Under the CMS-HCC V28 risk adjustment model, A54.42 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.209. Under the older V24 model, A54.42 mapped to the same category but with a base RAF weight of 0.482 — 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.
Verify documentation specifies gonococcal arthritis rather than other types of arthritis; the causative organism must be identified as gonorrhea. Because A54.42 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 A54.42 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies gonococcal arthritis rather than other types of arthritis; the causative organism must be identified as gonorrhea
- •Determine if the condition is acute or chronic, and identify the specific joint(s) affected, as additional codes may be needed for laterality and site specificity
Clinical Significance
Gonococcal arthritis is the most common musculoskeletal manifestation of disseminated gonococcal infection, typically presenting as acute monoarticular or oligoarticular septic arthritis. It requires urgent joint aspiration and IV antibiotics to prevent permanent joint destruction and reflects significant acute illness complexity.
Documentation Requirements
- ✓Positive Neisseria gonorrhoeae culture from synovial fluid or blood, or positive NAAT
- ✓Specific joint(s) affected with laterality documented
- ✓Synovial fluid analysis results (WBC count, Gram stain, culture)
- ✓Clinical presentation: acute onset, joint swelling, erythema, limited range of motion
- ✓Documentation of whether the infection is acute or chronic, and treatment response
Excludes 2 — Not included here, may code separately
- gonococcal infection of spine (A54.41)