ICD-10-CM > A00-B99 > B25-B34 > B27 > B27.9 B27.9 Infectious mononucleosis, unspecified Non-Billable/Non-Specific Codes B27.90Infectious mononucleosis, unspecified without complicationB27.91Infectious mononucleosis, unspecified with polyneuropathyB27.92Infectious mononucleosis, unspecified with meningitisB27.99Infectious mononucleosis, unspecified with other complication