B27: Infectious mononucleosis
Codes under B27 (Infectious mononucleosis). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| B27.0 | Gammaherpesviral mononucleosis | — |
| B27.0 | Gammaherpesviral mononucleosis | — |
| B27.00 | Gammaherpesviral mononucleosis without complication | ✓ |
| B27.00 | Gammaherpesviral mononucleosis without complication | ✓ |
| B27.01 | Gammaherpesviral mononucleosis with polyneuropathy | ✓ |
| B27.01 | Gammaherpesviral mononucleosis with polyneuropathy | ✓ |
| B27.1 | Cytomegaloviral mononucleosis | — |
| B27.1 | Cytomegaloviral mononucleosis | — |
| B27.02 | Gammaherpesviral mononucleosis with meningitis | ✓ |
| B27.02 | Gammaherpesviral mononucleosis with meningitis | ✓ |
| B27.8 | Other infectious mononucleosis | — |
| B27.8 | Other infectious mononucleosis | — |
| B27.09 | Gammaherpesviral mononucleosis with other complications | ✓ |
| B27.09 | Gammaherpesviral mononucleosis with other complications | ✓ |
| B27.9 | Infectious mononucleosis, unspecified | — |
| B27.9 | Infectious mononucleosis, unspecified | — |
| B27.10 | Cytomegaloviral mononucleosis without complications | ✓ |
| B27.10 | Cytomegaloviral mononucleosis without complications | ✓ |
| B27.11 | Cytomegaloviral mononucleosis with polyneuropathy | ✓ |
| B27.11 | Cytomegaloviral mononucleosis with polyneuropathy | ✓ |
| B27.12 | Cytomegaloviral mononucleosis with meningitis | ✓ |
| B27.12 | Cytomegaloviral mononucleosis with meningitis | ✓ |
| B27.19 | Cytomegaloviral mononucleosis with other complication | ✓ |
| B27.19 | Cytomegaloviral mononucleosis with other complication | ✓ |
| B27.80 | Other infectious mononucleosis without complication | ✓ |
| B27.80 | Other infectious mononucleosis without complication | ✓ |
| B27.81 | Other infectious mononucleosis with polyneuropathy | ✓ |
| B27.81 | Other infectious mononucleosis with polyneuropathy | ✓ |
| B27.82 | Other infectious mononucleosis with meningitis | ✓ |
| B27.82 | Other infectious mononucleosis with meningitis | ✓ |
| B27.89 | Other infectious mononucleosis with other complication | ✓ |
| B27.89 | Other infectious mononucleosis with other complication | ✓ |
| B27.90 | Infectious mononucleosis, unspecified without complication | ✓ |
| B27.90 | Infectious mononucleosis, unspecified without complication | ✓ |
| B27.91 | Infectious mononucleosis, unspecified with polyneuropathy | ✓ |
| B27.91 | Infectious mononucleosis, unspecified with polyneuropathy | ✓ |
| B27.92 | Infectious mononucleosis, unspecified with meningitis | ✓ |
| B27.92 | Infectious mononucleosis, unspecified with meningitis | ✓ |
| B27.99 | Infectious mononucleosis, unspecified with other complication | ✓ |
| B27.99 | Infectious mononucleosis, unspecified with other complication | ✓ |
Frequently asked questions
What is ICD-10-CM code B27?
B27 is an ICD-10-CM category covering Infectious mononucleosis. It contains 40 more specific diagnosis codes, 32 of which are billable.
Is B27 a billable code?
No — B27 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example B27.0 — Gammaherpesviral mononucleosis). 32 of the 40 codes under B27 are billable.
What codes fall under B27?
B27 includes B27.0, B27.0, B27.00, B27.00, B27.01, plus 35 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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