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B27.99

B27.99: Infectious mononucleosis, unspecified with other complication

Billable / specific codeICD-10-CM

B27.99 is a billable, specific ICD-10-CM code for infectious mononucleosis, unspecified with other complication. It is valid for submission on a claim.

Check B27.99 with the rest of the claim: free scrubber

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Hepatomegaly in unspecified infectious mononucleosis

Other codes that can never be billed with B27.99

Their own Excludes1 notes name this code, so the conflict is not listed above.

  • G02Meningitis in other infectious and parasitic diseases classified elsewhere
  • J02.8Acute pharyngitis due to other specified organisms
  • D72.821Monocytosis (symptomatic)

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Alphabetic index entries that lead here

  • Mononucleosis, infectious›with›complication NEC

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under B27.9

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.