B25.0
BillableCytomegaloviral pneumonitis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is B25.0 an HCC code?
Yes. B25.0 maps to Opportunistic Infections under the CMS-HCC V28 risk adjustment model (and Opportunistic Infections 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 B25.0
For B25.0to 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 B25.0 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
B25.0 is the ICD-10-CM diagnosis code for cytomegaloviral pneumonitis. A lung infection caused by cytomegalovirus (CMV), a common viral infection in people with weakened immune systems. B25.0 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other viral diseases (b25-b34).
Under the CMS-HCC V28 risk adjustment model, B25.0 maps to Opportunistic Infections (HCC 6) with a community, non-dual, aged base RAF weight of 0.439. Under the older V24 model, B25.0 mapped to the same category but with a base RAF weight of 0.440 — 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.
This code is commonly seen in immunocompromised patients such as those with HIV/AIDS or post-transplant. Because B25.0 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 B25.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code is commonly seen in immunocompromised patients such as those with HIV/AIDS or post-transplant
- •Ensure documentation specifies pneumonitis (lung inflammation) rather than other CMV manifestations
Clinical Significance
Cytomegaloviral pneumonitis is a serious opportunistic lung infection occurring almost exclusively in immunocompromised patients, particularly those with HIV/AIDS, organ transplant recipients, or patients on immunosuppressive therapy. It carries high mortality if untreated and reflects significant acute illness burden.
Documentation Requirements
- ✓CMV confirmed by bronchoalveolar lavage culture, PCR, or lung biopsy showing CMV inclusion bodies
- ✓Chest imaging documenting pneumonitis pattern (bilateral interstitial infiltrates)
- ✓Underlying immunocompromised condition documented (HIV with CD4 count, transplant status, immunosuppressive medications)
- ✓Clinical symptoms: dyspnea, hypoxia, non-productive cough, fever
- ✓Antiviral treatment documented (ganciclovir, valganciclovir, or foscarnet)
Commonly Confused Codes
- •B25.9 (Cytomegaloviral disease, unspecified) — Unspecified CMV without site specification; use B25.0 when lung involvement is documented
- •J18.9 (Pneumonia, unspecified organism) — Generic pneumonia code; CMV pneumonitis has a specific code that captures the opportunistic nature
- •B59 (Pneumocystosis) — Another opportunistic lung infection in immunocompromised patients but caused by Pneumocystis jirovecii, not CMV