B27.12
BillableCytomegaloviral mononucleosis with meningitis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is B27.12 an HCC code?
No. B27.12 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
B27.12 is the ICD-10-CM diagnosis code for cytomegaloviral mononucleosis with meningitis. Infectious mononucleosis caused by cytomegalovirus that has caused meningitis, an inflammation of the brain and spinal cord membranes. B27.12 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other viral diseases (b25-b34).
B27.12 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Document that meningitis is a complication of CMV infection, not a separate unrelated condition.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for B27.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document that meningitis is a complication of CMV infection, not a separate unrelated condition
- •This complication is particularly important to note in immunocompromised patients