ICD-10 Code B27.92 – Infectious mononucleosis, unspecified with meningitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B27.92 – Infectious mononucleosis, unspecified with meningitis
What it is
This code identifies infectious mononucleosis, usually a viral illness, when meningitis is also documented and the specific organism is not stated. Use it only when the record supports both the mononucleosis diagnosis and meningeal involvement.
Clinical signs
Typical mononucleosis findings may include fever, sore throat, lymph node enlargement, and fatigue. With meningitis, documentation may also note headache, neck stiffness, photophobia, or other meningeal signs; clinical features vary, refer to documentation.
When to use this code
Use B27.92 when the provider documents infectious mononucleosis with meningitis and does not identify a more specific cause. It fits inpatient or outpatient records where the meningitis is linked to the mono diagnosis. If the chart only says “mono” or only “meningitis,” do not assume this code.
Do not use for
Do not use this code for infectious mononucleosis without meningitis, or for meningitis caused by a different organism. Check documentation if the record names EBV, another virus, or a noninfectious cause.
Coding tip
Code the meningitis only when the provider clearly connects it to infectious mononucleosis in the documentation.