B27.00 Gammaherpesviral mononucleosis without complication

ICD-10-CM B27.00: Gammaherpesviral mononucleosis without complication

ICD-10-CM code B27.00 represents gammaherpesviral mononucleosis without complication. Public sources identify this code within a hierarchy that includes B27.01 and B27.02 for cases with complications. CMS billing articles list B27.00 in contexts involving non-oncologic conditions and rituximab, providing operational coding context rather than personal medical advice or a coverage guarantee. 1 2 3

Plain-language overview

ICD-10-CM code B27.00 identifies a diagnosis of gammaherpesviral mononucleosis without complication. This code distinguishes the condition from other forms of mononucleosis that involve specified complications. 3

What this code represents

Code B27.00 represents a specific diagnosis within the ICD-10-CM system. The official label for this diagnostic concept is gammaherpesviral mononucleosis without complication. 3

Coding details

The code B27.00 exists within a broader category that includes B27.01 for gammaherpesviral mononucleosis with polyneuropathy and B27.02 for gammaherpesviral mononucleosis with other complications. 3

A CMS billing and coding article for chemotherapy agents for non-oncologic conditions lists B27.00 alongside a code for stem cells transplant status and a code for gammaherpesviral mononucleosis with other complications. 1

Documentation considerations

A CMS billing and coding article for rituximab includes B27.00 within guidelines that contain billing, coding, or other guidelines. This article also lists D59.0 for drug-induced autoimmune conditions in the same context. 2

What the sources add

The CMS articles and the Unbound Medicine source provide different operational contexts. The CMS articles place B27.00 within billing guidelines for specific medical treatments, while the Unbound Medicine source establishes the code hierarchy and related complication codes. 1 2 3

The CMS rituximab article presents code B27.00 in a context that includes billing, coding, or other guidelines. This differs from the Unbound Medicine source, which lists the code without referencing specific treatment or billing guidelines. 2 3

Coverage and utilization context

The CMS article on chemotherapy agents for non-oncologic conditions places code B27.00 in a group that includes Z94.84 for stem cells transplant status. This placement provides context for billing and coding guidelines related to non-oncologic conditions. 1

Sources

1. Article - Billing and Coding: Chemotherapy Agents for Non-Oncologic Conditions (A55639) — cms.gov; accessed 2026-07-25.
2. Article - Billing and Coding: Rituximab (A56380) — cms.gov; accessed 2026-07-25.
3. B27.0 - Gammaherpesviral mononucleosis | ICD-10-CM — unboundmedicine.com; accessed 2026-07-25.