ICD-10-CM
ICD-10 code for Mononucleosis: B27.90
The ICD-10-CM index points "Mononucleosis" to B27.90, Infectious mononucleosis, unspecified without complication. B27.90 is a billable code.
Source: CDC ICD-10-CM FY2027 Alphabetic Index file dated June 16, 2026. Publisher page
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Index subterms
A header groups codes and is not billed. A billable code is one you can report.
- B27.10cytomegaloviral, Cytomegaloviral mononucleosis without complicationsBillable
- B27.00Epstein-Barr (virus), Gammaherpesviral mononucleosis without complicationBillable
- B27.00gammaherpesviral, Gammaherpesviral mononucleosis without complicationBillable
- B27.80specified NEC, Other infectious mononucleosis without complicationBillable
More specific codes in B27
A header groups codes and is not billed. A billable code is one you can report.
- B27Infectious mononucleosisHeader
- B27.0Gammaherpesviral mononucleosisHeader
- B27.00Gammaherpesviral mononucleosis without complicationBillable
- B27.01Gammaherpesviral mononucleosis with polyneuropathyBillable
- B27.02Gammaherpesviral mononucleosis with meningitisBillable
- B27.09Gammaherpesviral mononucleosis with other complicationsBillable
- B27.1Cytomegaloviral mononucleosisHeader
- B27.10Cytomegaloviral mononucleosis without complicationsBillable
- B27.11Cytomegaloviral mononucleosis with polyneuropathyBillable
- B27.12Cytomegaloviral mononucleosis with meningitisBillable
- B27.19Cytomegaloviral mononucleosis with other complicationBillable
- B27.8Other infectious mononucleosisHeader
- B27.80Other infectious mononucleosis without complicationBillable
- B27.81Other infectious mononucleosis with polyneuropathyBillable
- B27.82Other infectious mononucleosis with meningitisBillable
- B27.89Other infectious mononucleosis with other complicationBillable
- B27.9Infectious mononucleosis, unspecifiedHeader
- B27.90Infectious mononucleosis, unspecified without complicationBillable
- B27.91Infectious mononucleosis, unspecified with polyneuropathyBillable
- B27.92Infectious mononucleosis, unspecified with meningitisBillable
- B27.99Infectious mononucleosis, unspecified with other complicationBillable
Related conditions
Related pages
- B27.90 code detailsNotes, nearby codes, CMS-HCC group
- Category B27Every code under it
- Chapter 1Certain infectious and parasitic diseases
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Mononucleosis?
The ICD-10-CM index points "Mononucleosis" to B27.90, Infectious mononucleosis, unspecified without complication. B27.90 is a billable code.
Is B27.90 billable?
Yes. B27.90 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What chapter is B27.90 in?
Chapter 1. Certain infectious and parasitic diseases.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.