B27 vs J02.8
B27 and J02.8 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on J02.8
acute pharyngitis due to infectious mononucleosis (B27.-)
B27
Infectious mononucleosis
Not billable
- Chapter 1
- Certain infectious and parasitic diseases
- Section
- B25-B34
Use when the record says
- glandular fever
- monocytic angina
- Pfeiffer's disease
J02.8
Acute pharyngitis due to other specified organisms
BillableUnspecified
- Chapter 10
- Diseases of the respiratory system
- Section
- J00-J06
Indexed under
- Pharyngitis › pneumococcal (acute) (catarrhal)(gangrenous) (infective) (malignant) (membranous) (phlegmonous) (pseudomembranous) (simple) (subacute) (suppurative) (ulcerative)
- Pharyngitis › specified organism NEC (acute) (catarrhal)(gangrenous) (infective) (malignant) (membranous) (phlegmonous) (pseudomembranous) (simple) (subacute) (suppurative) (ulcerative)
- Pharyngitis › staphylococcal (acute) (catarrhal)(gangrenous) (infective) (malignant) (membranous) (phlegmonous) (pseudomembranous) (simple) (subacute) (suppurative) (ulcerative)
- Pharyngitis › viral NEC (acute) (catarrhal)(gangrenous) (infective) (malignant) (membranous) (phlegmonous) (pseudomembranous) (simple) (subacute) (suppurative) (ulcerative)
- Sore › throat › viral NEC
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027