B27.99 ICD-10-CM Code: Infectious mononucleosis, unspecified with other complication
B27.99 is the billable ICD-10-CM code for “Infectious mononucleosis, unspecified with other complication” in the FY 2027 U.S. code set, effective Oct 1, 2026.
Official description
B27.99Infectious mononucleosis, unspecified with other complication
ICD-10-CM diagnosis code · United States clinical modification
Where B27.99 sits
- 1
Chapter 1
Certain infectious and parasitic diseases (A00-B99)
- 2
Section
Other viral diseases (B25-B34)
- 3
Category B27
Infectious mononucleosis
- 4
Subcategory B27.9
Infectious mononucleosis, unspecified
- 5
Code B27.99
Infectious mononucleosis, unspecified with other complication
Notes for this code
Inclusion terms
- Hepatomegaly in unspecified infectious mononucleosis
Code first
No “code first” instruction is listed for B27.99.
Use additional code
No “use additional code” instruction is listed for B27.99.
Excludes1
Conditions that should not be reported together with this code.
No Excludes1 note is listed for B27.99.
Excludes2
Conditions not included here that may be reported separately when present.
No Excludes2 note is listed for B27.99.
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.
Frequently asked questions
What does ICD-10-CM code B27.99 mean?
B27.99 is the FY 2027 U.S. ICD-10-CM code for “Infectious mononucleosis, unspecified with other complication.”
Is B27.99 a billable or specific ICD-10-CM code?
Yes. In the FY 2027 reference data used on this page, B27.99 has no child codes and is presented as a billable/specific code. Always confirm the active code set and payer requirements before use.
Where is B27.99 located in ICD-10-CM?
B27.99 is listed in Chapter 1, Certain infectious and parasitic diseases (A00-B99), within Other viral diseases (B25-B34) (B25–B34), under category B27, Infectious mononucleosis and subcategory B27.9, Infectious mononucleosis, unspecified.
What coding notes are listed for B27.99?
Its listed inclusion terms are Hepatomegaly in unspecified infectious mononucleosis. No code-first instruction is listed. No Excludes1 note is listed. No Excludes2 note is listed.