Non-Billable / Non-Specific Code
ICD-10-CM B27.9 is the diagnosis code for Infectious mononucleosis, unspecified. This code falls under the section "Other viral diseases" within Chapter 1 — Certain infectious and parasitic diseases (A00-B99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where B27.9 sits in the ICD-10-CM classification helps ensure proper coding:
No, B27.9 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
B27.9 is the ICD-10-CM diagnosis code for "Infectious mononucleosis, unspecified". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of B27.9 is B27 ("Infectious mononucleosis"). B27.9 provides a more specific classification within this category.
B27.9 is located in Section B25-B34 — "Other viral diseases" within Chapter 1 of the ICD-10-CM Tabular List.
B27.9 has 4 sub-code(s) that provide more specific detail: B27.90, B27.91, B27.92, B27.99.
Use B27.9 when the patients documented diagnosis matches "Infectious mononucleosis, unspecified" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Infectious mononucleosis, unspecified is B27.9.
No, B27.9 is non-billable. Use a more specific sub-code for primary diagnosis billing.
B27.9 is in Chapter 1 of the ICD-10-CM Tabular List.
Yes, B27.9 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.